Kevin Cooper v Ludgate House Limited

This is a claim by the owners of two leasehold flats in a building known as Bankside Lofts, at 65 Hopton Street, London SE1, for an injunction requiring the Defendant to demolish substantial parts of a new office building called “Arbor”, built recently at the junction of Southwark Street and Blackfriars Road, in London SE1. The Claimants allege that Arbor causes a nuisance by interfering with the rights of light that it is now admitted that they enjoy, appurtenant to their flats. In the alternative, the Claimants claim damages in lieu of injunctive relief, assessed on a negotiating damages basis, or alternatively damages for diminution in value of their flats caused by the nuisance.

Bankside Lofts, which was built by the Manhattan Loft Company between 1996 and 1998, stands on the east side of Hopton Street, which runs north from Southwark Street towards the River Thames and then curves round the end of Bankside Lofts towards the Tate Modern Museum on Bankside. The façade of Bankside Lofts faces west, towards a large development site created by the demolition of a building called Sampson House, which formerly stood on the west side of Hopton Street for most of its length (“the Sampson House site”). The Sampson House site adjoins on its west side the busy railway lines running south from Blackfriars Railway Station.

On the other side of the railway lines is another part of the development site, of a similar size, created in part by the demolition of Ludgate House on Blackfriars Road (“the Ludgate House site”). The two parts of the development site (which are linked by the arches and other land lying beneath the railway lines) are together known as Bankside Yards, and are being developed by Native Land. A plan of the development site is below:

The buildings to be built are marked on the plan as “BY1” to “BY9”, between Blackfriars Road and Hopton Street. Bankside Lofts is the building shown to the east of Hopton Street, and the Claimants’ flats in that building sit just to the north of the number “65” marked on the plan.

Planning permission for Bankside Yards was first granted to the previous owners, Carlyle Group, in 2014, and there have been further permissions granted and non-material amendments made since then. There are planned to be 8 large buildings in total, but it is expected that it may be 15 years before the development as a whole is completed, if indeed it is.

It is on the southern part of the Ludgate House site, next to Blackfriars Road, that Arbor has been built. The massing was completed in November 2021 and practical completion was in December 2022. It stands 19 storeys high. Next to it, a second tower, known as “Opus”, intended for residential use, is in course of construction. It will be 48 storeys high when it is topped out later this year and is scheduled for completion in 2027. At present, the remaining parts of both sites are undeveloped, save in part at basement level.

Each half of the development site is owned by a different special purpose vehicle: the Ludgate House site by the Defendant (which I refer to as “the Defendant” or “LHL”), and the Sampson House site by Sampson House Limited (“SHL”). LHL and SHL are each wholly owned by a company called Bankside Yards (Jersey) Limited (“BY Jersey”). Native Land is a minority shareholder of BY Jersey and is the appointed development manager for Bankside Yards. I refer to Native Land hereafter as “the developer”, though BY Jersey is the beneficial owner of the development site.

Mr Cooper’s flat, which he bought in about March 2021, is flat 705, on the seventh floor of Bankside Lofts. It comprises 3 bedrooms, two bathrooms (one ensuite) and a large living/kitchen/dining room (“LKD”). The LKD is very much a feature of the flat, as it is relatively large and has a triple aspect, facing east, south and west, and enjoys a large, mainly south-facing terrace. It is common ground that this room enjoys and will continue to enjoy particularly good light.

Two of the bedrooms in flat 705, including the principal bedroom, face west only. It is the principal bedroom that it is claimed will suffer an actionable reduction in its light.

Mr and Mrs Powell’s flat, which they bought in 2001, is flat 605, on the sixth floor of Bankside Lofts. It comprises two bedrooms, two bathrooms (one ensuite) and an LKD. All the rooms (except for an internal bathroom) face west. Flat 605 is smaller than flat 705, and, although it has a smaller terrace outside its LKD, it is not as strikingly well-lit as the equivalent room in flat 705, partly because it has no southerly aspect, and partly because the floor to ceiling height is rather low by modern standards (and not what one would expect in this kind of development). It is claimed that the LKD and the principal bedroom in flat 605 will suffer an actionable loss of light.

It is an oddity of this case that, although Arbor deprives the Claimants of some light, neither flat currently suffers from insufficient light in any of its rooms. That is because Sampson House, which originally stood 2-3 storeys higher than Bankside Lofts and was in place for much of the period of 20 years during which the rights of light were acquired, was demolished in 2019, and nothing currently stands in its place. The light enjoyed by the flats was thereby temporarily substantially improved by additional light, to which the Claimants have acquired no right; though that improvement may prove temporary, and is now being reduced as a result of the construction of Opus.

The greatest impact on the light currently enjoyed in flats 605 and 705 will be felt if the new buildings planned for the Sampson House site are built, in future years. The developer has planning permission for towers of 32 and 30 storeys on the part of the Sampson House site nearest to Bankside Lofts (buildings BY5 and BY6).

As a result of a resolution made by the Council of the London Borough of Southwark (“the Council”) on 18 January 2022 pursuant to section 203 of the Housing and Planning Act 2016 (“the s.203 resolution”), and following transfers of title to the two parts of the development site thereafter (to the Council and back again to LHL and SHL), Native Land became entitled to build the remainder of the development (excluding Arbor) notwithstanding the admitted interference that that will cause with adjoining owners’ rights to light. The Claimants will not be able to rely on their rights of light to prevent that development taking place. Under section 204 of the 2016 Act, the affected owners, including the Claimants, will be able to claim compensation, on a diminution in value basis only, for the loss of their light caused by the construction of the protected development. I will refer to that protected development hereafter as “the 203 development”, as the parties did, but it is important to remember that it excludes Arbor.

Although the Claimants’ rights of light over the 203 development have not been abrogated, their ability to enforce them to protect the access and use of light to their flats has been removed in relation to any development carried out on the 203 development site pursuant to the planning permission, or any variant of it (and probably any replacement permission for a Bankside Yards scheme too). Prior to May 2022, when the transfers of title were completed, the Claimants would have been entitled to assert their rights against Opus, or BY5 and BY6, even if they had not objected to the construction of Arbor; but as from that time, they are only able to seek to enforce their rights against Arbor.

There is a lively dispute about the appropriate basis for assessing the impact that Arbor has had (or will be seen in due course to have had) in these circumstances. The issue has never previously had to be addressed in a case where s.203 or its statutory predecessor, s.237 of the Town and Country Planning Act 1990, has been invoked, or (as far as is known) in other cases where works that contribute to an obstruction of light were authorised by an Act of Parliament and so immune from restraint for that reason.

The Claimants’ primary case is that the light that will be lost in due course when the 203 development is built must be left out of account in assessing whether the erection of Arbor is an actionable nuisance. That is because the effect of the s.203 resolution is that the Claimants can no longer protect the light passing over the 203 development site, even though they have rights of light; and accordingly that light should be ignored in the same way that light to which an objector has no right is ignored for this purpose. The appropriate comparison (the Claimants say), when assessing whether Arbor causes a nuisance, is between the amount of protectable light coming into the flats before Arbor was built (the “Before” assessment) and the volume of protectable light after Arbor is built (the “After” assessment). Since the light that would be blocked by the 203 development cannot be protected, it is to be left out of account in both assessments. This scenario was referred to by the parties as “CS1”. For the purposes of calculation, it assumes that the other towers on the 203 development site have been built, but only as a means of eliminating from the assessment the light that they will block.

The Claimants also have a secondary case, which involves an attempt to equalise the burden of the Claimants’ rights of light across the different parts of the Sampson House site and the Ludgate House site (scenario “CS2”), so that no one part of the site can be built up beyond a level that allows each other part to be built to the same level without causing a nuisance to the Claimants. There is a dispute, first, about whether this is a correct approach in principle; second, if it is, whether the principle should be applied on the facts of this case; and third, if it should, whether the Claimants and their expert light surveyor have gone about it in the right way.

The Defendant’s case, on the other hand, is that light coming over the 203 development site at present should be taken into account, because it is there and because the s.203 resolution does nothing to deprive the Claimants of their rights of light: it just changes the remedy to which they will be entitled if and when the remaining parts of the 203 development cause a reduction in their light. The Defendant contends that the appropriate comparison is therefore between – as the “Before” assessment – the volume of light that was enjoyed when Sampson House and Ludgate House existed (since the Claimants cannot have acquired rights in relation to light passing over those parts of the airspace on the two sites) and – as the “After” assessment – the volume of that light that remains with Arbor additionally in place (scenario “DS1”).

Unsurprisingly, these three different comparisons produce significantly different results. On scenario DS1, Mr and Mrs Powell eventually accepted that they could not establish an actionable loss of light. Whether the reduction in light caused to Mr Cooper on scenario DS1 is actionable is disputed on the expert evidence.

It can therefore be seen that a very important question is whether, in view of the s.203 resolution, the Claimants should be treated as having effectively lost the long term benefit of light from the 203 development site, or whether they should be treated as still able to enjoy it, on the basis that they will be compensated for its loss separately in future. It is the first time that this issue has arisen in a case, as far as is known.

Apart from the debate about the appropriate scenario to use as the basis of Before and After comparison, there is an equally lively dispute about the appropriate way to measure the loss of light, in each of the scenarios contended for, for the purpose of determining whether there has been an actionable interference. The traditional method in rights of light cases is the Waldram method, named after the chartered surveyor who created it, Percy Waldram. This remains the standard method of assessment, used by the whole of the industry. It uses visibility - at working plane level in a room - of a small proportion of the sky as a proxy for identifying the proportion of the room that is well lit, with a proportion below 50% indicating that the room as a whole is poorly lit. The Claimants rely exclusively on that method, as their expert light surveyor contends that alternative methods are not appropriate or reliable as a means of assessing whether there has been an actionable loss of light.

The Defendants contend that the Waldram methodology is outmoded and liable to produce incorrect results, and does so in these cases. They rely instead – ultimately exclusively – on a different approach to measuring levels of illuminance in a room, called the Radiance methods, after the proprietary software that is used. This is based on various sunlight and daylight assessments and determines whether, in average conditions of external brightness, at least half the room will be lit to a minimum standard of illuminance. These methods, which are based on a British Standard that is in turn based on a European Standard, are regularly used in a planning context, as an aid both to design of buildings and achievement of minimum standards. Guidance issued by the British Research Establishment explains these methods further and also includes different assessments that can be used to indicate whether the construction of a new building is likely to cause a significant impact on the use of existing property, again for planning purposes. These methods were not designed or calibrated to measure whether the light remaining after an obstruction is sufficient for the ordinary purposes of occupiers of the property affected. They have only once previously been used to attempt to answer the specific questions arising in a rights of light context: in a recent case called Beaumont Business Centres Ltd v Florala Properties Ltd [2020] EWHC 550 (Ch).

Again, the various methodologies produce some different results (though not entirely different), which in this case enable the Claimants to assert that there is a substantial interference with their lights and the Defendant to deny that the remaining light is insufficient or that any reduction in light is noticeable or substantial.

If the Claimants establish a nuisance but injunctive relief is refused, for one or more of a number of reasons advanced by LHL, they seek negotiating damages. LHL denies that negotiating damages are appropriate in any right of light case, and say that the Claimants should only be compensated by an award that reflects the diminution in value of their flats caused by any actionable interference by Arbor.

If the Claimants are entitled to negotiating damages, it is common ground that the hypothetical negotiation should be assumed to have taken place in August 2019, just before the start of the works to build Arbor above ground level.

One important component of the assessment may be the reduction in value of the Arbor site attributable to the inability of LHL to build above a certain level – i.e. a scaled back version of Arbor could have been designed and built without infringing the rights of light, but that would have made the development and so the land less valuable.

On that basis, the parties’ development valuation expert witnesses have addressed the question of how much more the site of Arbor was worth, in August 2019, if Arbor could be built in full, rather than a reduced version of it or a different non-infringing building. That difference in value is not, of course, the measure of the negotiating damages: it is one component in the hypothetical negotiations between the Claimants and LHL for a payment to allow Arbor to proceed. As will become clear, there are also other significant factors that each side relied on.

Finally, the parties have adduced expert evidence on the value of the flats, for the purposes of assessing diminution in value (as at the date of trial) in the event that it is decided that only diminution in value damages are to be awarded.

The case raises many difficult and important questions, which I have attempted to answer as fully as is necessary to decide the cases.

The parties have helpfully agreed the issues and sub-issues that I need to address. They are the following:

Bankside Yards was originally assembled by Carlyle Group, who then obtained planning permission in 2014 for its development for mixed residential, office, hotel and retail uses.

The land was acquired by BY Jersey in 2015. A public consultation was carried out on its behalf between October 2017 and April 2018, following which an application for a revised planning permission was made in 2018. This was finally granted on 22 December 2020 and currently exists for 8 buildings above ground level, including Arbor and Opus. The location and scale of Arbor and the proposed other buildings to be built on Bankside Yards is shown on the image below. (Existing buildings are grey; Arbor is the green building; Opus is the indigo coloured building between Arbor and the river.) To date, nothing has been built above ground level on the Sampson House site.

The evidence from Mr Locke was that the next stages of the development will need to be funded (at least in part) by the proceeds of sale of the flats in Opus, so the next stage will not begin until after practical completion of Opus. Thereafter, the further buildings will be built in sequence, with the result that the last may not be completed within 15 years from today.

Opus (BY2) is close to being topped out. It is already having and will continue to have an impact on the light enjoyed by flats 605 and 705, though whether it and Arbor in combination will be an actionable infringement (triggering the Claimants’ rights to claim compensation under s.204) was not established. It will, however, be buildings BY5 and BY6, much closer to the façade of Bankside Lofts, that cause the greatest impact on the flats’ light.

A right of light is a negative easement appurtenant to a property (the dominant tenement) that benefits from the access of light over an adjoining or neighbouring property (the servient tenement). It is generally acquired by 20 years’ continuous actual enjoyment of light passing over the servient land and through windows (or other apertures) of the dominant property (s.3 Prescription Act 1832). The period of continuous enjoyment must be the period before the enjoyment of the light becomes contentious, leading to the proceedings brought to establish or enforce the rights claimed.

Alternatively, where use without interruption during that 20-year period cannot be established, proof of any period of 20 years’ enjoyment as of right without interruption will usually be sufficient to establish rights under the doctrine of lost modern grant, provided that the circumstances relating to the dominant and servient tenements justify a conclusion that the enjoyment must be attributable to an express grant made at some past time. The subtleties of the way in which rights are acquired need not be further discussed here, save for one point, since the acquisition of rights of light over the LHL site and the SHL site appurtenant to flats 605 and 705 is now not disputed in this case.

The one point to elaborate is that rights over particular parts of a servient tenement cannot be acquired by long enjoyment in this way unless there has been 20 years’ enjoyment of light over those parts. It is not sufficient to give rise to a right over the servient tenement as a whole that light has been enjoyed over some of it (Part A) for more than 20 years, if light over the rest (Part B) has only been enjoyed for less than 20 years. In those circumstances, a right of light exists over Part A only, and does not entitle the dominant owner to assert rights to the extent that sufficient light is attributable to Part B. Thus, the Claimants in this case have no right to the light from that part of the SHL site up to the height where Sampson House previously stood, as it was only demolished in about 2019. The Claimants have rights over that part of the SHL site at higher level only. That is why the Defendant’s DS1 scenario excludes from the assessment model light that the Claimants now enjoy over the Sampson House site at lower levels. And, similarly, in relation to any additional light released from the demolition of Ludgate House.

The fact that rights of light are negative easements means that, in an infringement claim, the focus is on whether the use and enjoyment of the dominant tenement has been adversely impacted. In particular, the question is not whether a substantial amount of light has been obstructed by the servient owner, but whether the light that remains to the dominant property is sufficient for the ordinary purposes of its occupiers. Since the cause of action for interference with the enjoyment of an easement is nuisance, not trespass, a claimant must prove that their enjoyment or use has been substantially harmed, as in law not every interference with enjoyment or use of property is actionable. An owner of property is expected to put up with a certain amount of disturbance and not sue for a small, temporary or inconsequential infringement: Fearn v Board of Trustees of the Tate Gallery [2023] UKSC 14; [2024] A.C. 1 (“Fearn v Tate Gallery”), at [22], [23].

I agree with the Defendant’s submission that, in considering whether there has been an actionable interference with the Claimants’ rights of light, it is necessary to start with a consideration of the nature of a right to light. That is relevant both to the issue of what is the correct “Before” and “After” comparison, when assessing the impact of Arbor, and to the issue of how light should be measured in order to inform the assessment of whether a substantial interference has occurred.

In the leading House of Lords decision of Colls v Home and Colonial Stores [1904] A.C. 179 (“Colls”), the Lord Chancellor, the Earl of Halsbury, explained that it was a misapprehension to say that a dominant owner was entitled after 20 years to all the light that he had enjoyed, and that any appreciable diminution in that light was actionable. He said, at p. 182:

“I do not think that is the law. The argument seems to me to rest upon a false analogy, as though the access to and enjoyment of light constituted a sort of proprietary right in the light itself. Light, like air, is the common property of all, or, to speak more accurately, it is the common right of all to enjoy it, but it is the exclusive property of none.”

And at pp. 184-185:

“The test of the right, I think, is whether the obstruction complained of is a nuisance, and, as it appears to me, the value of the test makes the amount of right acquired depend upon the surroundings and circumstances of light coming from other sources, as well as the question of the proximity of the premises complained of.”

For these reasons, it is fallacious to consider that a right to the enjoyment of a particular quantity of light through a defined aperture has been acquired by long use, or that any reduction of light is actionable.

In the same case, Lord Lindley said, at 212:

“The general principle deducible from [the authorities] appears to be that the right to light is in truth no more than a right to be protected against a particular form of nuisance, and that an action for the obstruction of light that has in fact been used and enjoyed for twenty years without interruption or written consent cannot be sustained unless the obstruction amounts to an actionable nuisance; and this often depends on considerations wider than the facts applicable to the complainant himself.”

In Kine v Jolly [1905] 1 Ch 480 at 487, Vaughan Williams LJ explained that in Colls the House of Lords had settled the question whether a right of light was a right to property or a right to prevent a landowner from using his land so as to constitute a nuisance to the owner or occupier of adjoining land in favour of the latter interpretation, and added, at 489 :

“… in all these cases of nuisance which involve a limitation of a man’s right to use his own land, the Courts will not enforce the alleged rights of the plaintiff, unless that which has occurred is a substantial interference with his comfortable or profitable occupation of his dwelling-house, or warehouse, or house of business, as the case may be. [….] [T]here can be no doubt that such a rule, whether logical or not, is a rule that owes its existence to the convenience and comfort of the people at large. It is convenient that no man should be allowed to enforce rights to such an extent as to interfere with the good and the progress of the community. That I understand to be the meaning of the decision of the House of Lords ….”

The philosophical underpinning of the decision in Colls can therefore be seen to be the substantial public interest in progress and development, which must, at times, override the protection of individual rights, provided that progress and development does not cause substantial harm to the use and enjoyment of private property. It is the law of nuisance that maintains this balance, as it has always done, by focusing on the degree of harm done to the utility and amenity value of the claimant’s land: see Fearn v Tate Gallery at [11], per Lord Leggatt. The interest protected by the law of nuisance is the utility of land, and whether there is or is no substantial interference is to be assessed objectively on that basis: ibid., at [22]-[23]. The focus is therefore on the use and occupation of land, not on the interests of an individual occupier. It is not every interference with use and occupation that is actionable.

The basis of the decision in Colls, and later authoritative decisions such as Kine v Jolly, which stress the need for substantial interference with comfortable occupation of a dominant dwelling-house, would of course have been understood by Percy Waldram when, in the 1920s, he set about devising his method for assessing whether or not there was an actionable interference with light. It is evident from other cases, where Waldram was an expert witness, that he did.

The focus where the question of infringement of light is in issue is not on what light has been taken away, however noticeable the change may be, but on what light remains. In his speech in Colls, Lord Macnaghten cited with approval the direction of Best C.J. to the jury in the case of Back v Stacey (1826) 2 C.& P. 265:

“It was not sufficient to constitute an illegal obstruction, that the plaintiff had, in fact, less light than before; nor that his warehouse, the part of his house principally affected, could not be used for all the purposes to which it might otherwise have been applied. In order to give a right of action, and sustain the issue, there must be a substantial privation of light, sufficient to render the occupation of the house uncomfortable, and to prevent the plaintiff from carrying on his accustomed business … on the premises as beneficially as he had formerly done. His Lordship added that it might be difficult to draw the line, but the jury must distinguish between a partial inconvenience and a real injury to the plaintiff in the enjoyment of the premises.”

The direction was also approved by Lord Lindley, at p.208, who said that it was a mistake to consider actionable any interference with the quantity of light that had been enjoyed before the obstruction, and that the correct position was that:

“ … generally speaking an owner of ancient lights is entitled to sufficient light according to the ordinary notions of mankind for the comfortable use and enjoyment of his home as a dwelling-house, if it is a dwelling-house, or for the comfortable use and enjoyment of the house if it is a warehouse, a shop, or other place of business. The expressions “the ordinary notions of mankind,” “comfortable use and occupation,” and “beneficial use and occupation” introduce elements of uncertainty; but similar uncertainty has always existed and exists still in all cases of nuisance…”

It is therefore a jury question – a question of fact and judgement – whether, applying the legal test in Colls, an actionable interference exists. The focus is on the comfortable use and enjoyment of the dominant tenement – the property itself – not on the comfortable use and enjoyment of a particular room: per Millett J in Carr-Saunders v Dick McNeil Associates Ltd [1986] 1 WLR 922.

It was, probably,the degree of uncertainty to which Lord Lindley refers that was the reason Waldram set about establishing a proxy for that judgement. Rights of light are rights acquired in fee simple, even when appurtenant to leasehold flats, and so the court is concerned with the comfortable use of the property for an unlimited time, not only for a defined period. As a result, it should take into account how a property may reasonably be enjoyed by others in future, and not solely with its current layout or mode of enjoyment.

Whether a particular activity constitutes a nuisance may depend on an assessment of the locality in which the activity is carried out. Belgrave Square and Bermondsey are, even today, locations with a different character and different expectations. However, an activity can still constitute a nuisance even though it conforms to the character of the locality: per Lord Neuberger of Abbotsbury PSC in Lawrence v Fen Tigers Ltd [2014] UKSC 13; [2014] A.C. 1 (“Fen Tigers”), at [4], [71]. Locality is only one factor.

The fact that the activity in dispute has planning permission may be relevant to an assessment of the character of the locality, though the thing permitted cannot itself determine that character, to the extent that it constitutes a nuisance; and the existence of planning permission is not a major determinant of liability, even where the grant relates to a major strategic development: Fen Tigers at [94]-[96] (per Lord Neuberger), [156] (per Lord Sumption), and [162] (per Lord Mance), Lord Carnwath dissenting on this point at [222]-[224].

The unusual factor in this case is the interplay between the established principles of rights of light, summarised above, and planning legislation, which authorises a local planning authority to agree to acquire land for the purpose of facilitating development.

Section 203 of the Housing and Planning Act 2016 (the successor to section 237 of the Town and Country Planning Act 1990 in similar terms) provides, so far as material:

“(1)

A person may carry out building or maintenance works to which this subsection applies even if it involves –

(a)

interfering with a relevant right or interest, or

(b)

breaching

(i)

a restriction as to the user of land arising by virtue of a contract, or

(ii)

an obligation under a conservation covenant.

(2)

Subsection (1) applies to building or maintenance work where --

(a)

there is planning consent for the building or maintenance work,

(b)

the work is carried out on land that has at any time on or after the relevant day –

(i)

become vested in or acquired by a specified authority or a specified company acting on behalf of a specified authority, or

(ii)

been appropriated by a local authority for planning purposes as defined by section 246(1) of the Town and Country Planning Act 1990,

(c)

the authority could acquire the land compulsorily for the purposes of the building or maintenance work, and

(d)

the building or maintenance work is for purposes related to purposes for which the land was vested, acquired or appropriate as mentioned in paragraph (b).”

A relevant right or interest includes any easement annexed to land and adversely affecting other land, and a specified authority includes a local authority (s.205(1)).

The section therefore authorises interference with a right to light if the conditions in subsection (2) are satisfied, in particular that the building work is for purposes related to purposes for which the land was acquired by the local authority.

Section 204(1) and (2) of the 2016 Act provide:

“(1)

A person is liable to pay compensation for any interference with a relevant right or interest or breach of a restriction that is authorised by section 203(1)(a) or (b)(i) …….

(2)

The compensation is to be calculated on the same basis as compensation payable under sections 7 and 10 of the Compulsory Purchase Act 1965.”

The resolutions made by the Council, dated 18 January 2022, are to enter into agreements with LHL and SHL to acquire the freeholds and grant 999-year leases back:

“… for the purpose of facilitating the carrying out of development, redevelopment or improvement on or in relation to that land”.

They were therefore, deliberately, in broad terms, and would have effect in relation to the carrying out of any development, provided that it was related to the purposes for which the land was acquired by the Council, which is stated on the published public record of the meeting as being “to facilitate the delivery of the Bankside Yards Project”.

Generally speaking, the s.203 power is not used unless the authority is satisfied that, without it, beneficial development would be prevented. The Council had adopted a policy that the exercise of the statutory powers should be a last resort, when genuine negotiations with affected persons had failed. That position had not been reached in January 2022 and the Council determined to depart from it, having consulted local owners and occupiers. No judicial review challenge was made to the s.203 resolution.

The Act also contemplates that the authority will acquire the land – but nothing in the legislation prevents a subsequent sale of the land to a developer. Indeed, in most cases, one would not expect the local authority to be the ultimate developer. In this case, the transfer to the Council, the grant of long leases to LHL and SHL, the re-transfer of the freehold subject to the leases, and the immediate merger of the leasehold titles were all pre-arranged steps, and so only a means to enable the developer to proceed with the 203 development without having to worry about rights of light. However, there was and is no legal challenge to its validity.

The clear consequence is that, if and when the s.203 development proceeds to such a stage where there is actionable interference with the Claimants’ light, the Claimants will be entitled to claim statutory compensation for the diminution in value caused by the 203 development (but not by Arbor, which was built out before the s.203 resolution of the Council).

It is convenient at this point to refer to the instructions given to the expert light surveyors on the questions that they should address. These were:

The Defendant contends that questions (i) and (iii) are necessary questions before it is possible to conclude that the construction of Arbor is in law a nuisance to either flat. It accepts that question (ii) is only a ‘threshold’ question, the answer to which may assist in answering question (iii). It contends that if a loss of light is not noticeable, it cannot on any basis have a substantial adverse effect on the use and enjoyment of a flat. The Claimant’s position is that if the correct analysis of reduction of light in each flat is applied (sc. the Waldram method), questions (ii) and (iii) are otiose: if there is insufficient light left for ordinary use and enjoyment, then there is for that reason a substantial adverse effect on use and enjoyment, and in law a nuisance. They contend that the Waldram method is calibrated to determine this point, since any property that becomes insufficiently lit for ordinary use has been substantially adversely affected by the obstruction, by definition. (The position may be more subtle when considering the impact of an obstruction on a property that is already insufficiently lit.)

The Defendant sought to argue that it was common ground that the three questions (or at least questions (i) and (iii)) were legally relevant questions, on the basis that the questions for the surveyors had been agreed. I do not accept that, though it is common ground that question (i) is legally relevant. I agree with the Claimants that the questions derive from the pleaded cases, and were agreed to be relevant questions to be addressed by the expert light surveyors, given the parties’ pleaded cases. The Claimant is not thereby precluded from arguing that either or both of questions (ii) and (iii) are irrelevant; and even if they were, that would not preclude the court from considering whether question (iii) is an independent test that must be separately answered, and whether question (ii) has any bearing on question (iii).

I turn now to the first of the main questions that I have to decide: whether CS1, CS2 or DS1 is the appropriate basis for the Before and After comparison for each flat.

Given that the issue of infringement is determined by what light remains to the dominant owner, not what light has been taken away, it is necessary first to identify whether sufficient light remains in each flat for the ordinary purposes of the occupier, and then where that light comes from – whether from other parts of the servient tenement, or from elsewhere, or both. The next question is whether all or any of that light is to be taken into account in assessing whether sufficient light remains for ordinary purposes.

There is no doubt that, in general, all remaining light from other parts of the servient tenement can be taken into account if the dominant tenement has a right to that light, or if, although there is no right to it, in practice that light will assuredly remain available to the dominant tenement in perpetuity. That is established by Colls itself, by the later cases of Sheffield Masonic Hall Co v Sheffield Corporation [1932] 2 Ch 17(“Sheffield Masonic”) and Smith v Evangelization Society (Incorporated) Trust[1933] 1 Ch 515 (“Smith”), and it was the subject of an earlier case called Dyer’s Company v King(1870) LR 9 Eq 438 (“Dyer’s case”). More difficult questions arise if the light comes from land in other ownership, or enters through different apertures, but that is not this case.

It is convenient to start with Dyer’s case, because that decision was the origin of dicta of Lord Lindley in Colls that the parties agree are fundamental to deciding whether CS1 is the correct scenario.

In Dyer’s case, the company’s property benefited from light over King’s adjoining property, some light passing over part of its own property that had been cleared, and also other light from property adjoining King’s that had been partially cleared 12 years or so previously. King proposed to raise the height of his building and the company objected. The works were restrained by the Court.

The decision is a little unsatisfactory for two reasons. First, despite James V-C indicating that he considered that only a question of law fell to be decided, he appears to have decided the case on the basis that King was wrong to say that there would be sufficient light remaining to the company for its use. It is not entirely clear whether that was because there was in fact insufficient light left or because in law it was not protectable light. Second, the argument about the light to which the company was entitled was affected by the heresy about property in certain quantities of light that was only laid to rest in Colls, 34 years later.

However, it appears that the judge had in mind the question whether in law the additional light provided by the clearances was protectable light, having not been enjoyed for 20 years, and that is reflected in the law reporter’s headnote. It also appears to be the understanding of Lord Lindley, who in Colls said that where an angle of 45 degrees is left to the dominant owner, there ought to be no infringement “especially if there is good light from other directions as well”, and then continued, at pp.210-211:

“As regards light from other quarters, such light cannot be disregarded; for as pointed out by James V.-C. in the Dyers Co v King, the light from other quarters, and the light the obstruction of which is complained of, may be so much in excess of what is protected by law as to render the interference complained of non-actionable. I apprehend, however, that light to which a right has not been acquired by grant or prescription, and of which the plaintiff may be deprived at any time, ought not to be taken into account. (See the case just cited.)” (emphasis added)

The critical question to which this principle gives rise is: is light of which a claimant may be deprived at any time, despite having a right to it, light that similarly ought not to be taken into account?

It is clear, in context, that Lord Lindley was referring to light coming to the dominant tenement from land other than the defendant’s servient tenement, which, as in Dyer’s case, gave rise to the question whether that was light that the plaintiff was assured of being able to continue to enjoy. The first sentence of the passage that I have quoted in [67] affirms the principle, decided in Colls, that the right of the dominant owner is to protect sufficient light, not all the light that has been enjoyed for 20 years. Light enjoyed from elsewhere (“other quarters”) could be a reason why there is no infringement of light caused by the obstruction, just a diminution in the amount of light. The second sentence qualifies the first, and the principle is clear, namely that light to which there is no right, which cannot be protected, should not be taken into account.

The Defendant submits that Lord Lindley specifies two conditions for leaving light out of account: the absence of a right to light, and the risk of losing the light. The Claimant submits that the key consideration was whether the light might in practice be lost, which would generally be the case if no right to it existed.

In Sheffield Masonic, the plaintiff’s house was on a corner plot and received light from separate windows facing north and facing east. It had rights to light from both directions. To the north, the Corporation built a large library and gallery. To the east, stood only a 2-storey building. The issue was whether the reduction in light from the north was sufficiently compensated by the remaining light from the east. Maugham J held that, although the remaining light from the east was sufficient, the Corporation was not entitled to build as high as it pleased, thereby throwing all the burden of the rights of light onto the land to the east in different ownership. The Corporation had created a nuisance because it potentially left the plaintiff with insufficient light, even though the adjoining owner was not about to build, and in the meantime the house enjoyed sufficient light. This decision therefore establishes that even where a claimant has a right to light from other quarters in different ownership, and the aggregate remaining light is sufficient, there may nevertheless be an infringement by the defendant if the right to other light cannot be enforced.

Sheffield Masonic turns on the fact that there were different windows facing servient tenements in different ownership. Had the Corporation owned both tenements, the outcome would have been different. It is common ground that there can be no complaint about the same servient owner choosing to transfer all the burden to one part of its land by building on one part of it (see Davis v Marrable [1913] 2 Ch 421). The outcome also depended on an assumed principle that different servient owners are entitled to build equally, so sharing the burden of rights of light affecting them all, rather than the first in time to build transferring the full burden to the others.

The decision has been subject to academic criticism. The Defendant argued that it was wrongly decided, and that the correct analysis should be that the Corporation’s building was not actionable unless and until the adjoining servient owner also built. At that time, both buildings would be actionable interferences with the dominant owner’s rights of light because they amount jointly to a substantial interference with light, even though one building individually was not. This principle of cumulative joint infringement is said to be established by the decision in Thorpe v Brumfitt (1873) LR 8 Ch App 650, per James LJ at 656-7, a decision on obstruction of a right of way. The Claimant contends that Sheffield Masonic was correctly decided, and that, importantly, it illustrates that even when a right of light exists, the necessary amount of light may not be able to be protected.

In Smith, the issue was whether a right to sufficient light had been acquired over land to the west of the dominant tenement. The proposed building of the neighbouring owner would make the remaining light insufficient unless the light from skylights that the dominant owner had recently removed from his property were taken into account. Maugham J held that the jury should be directed to take the light from the skylights into account. On appeal, the respondent argued that the court should not take into account other light that can be interfered with, and Romer LJ is recorded at p.288 as suggesting that “[i]t can make no difference whether the light to be taken into account is an ancient light or in fact a light which cannot be obstructed”. That suggests that light that would in fact remain available, whether there was a right to it or not, should be taken into account.

As Mr Calland pointed out, the same point is made in Romer LJ’s judgment (at pp.539-540), commenting on the passage from Lord Lindley’s judgment at [67] above, where he says: “… it is not all light to which a right has not been acquired by grant or prescription that is left out of account, but only the light of which the plaintiff may be deprived at any time”. These words can be said to cut both ways: on the one hand, Romer LJ was addressing light to which a right had not been acquired, not a case where there was a right of light; on the other hand, he did not consider that what should be left out of account was determined solely be asking whether there was or was not a right to the light. Lawrence LJ, in his judgment in Smith, similarly focused on the practical consequences. He stated the principle established by Colls and recognised by Maugham J as being that the court “must have regard to other sources of light which the room possesses, disregarding, however, any access of light of which the plaintiff may be deprived at any time” (p.535). These observations, and the decision that light formerly entering through the skylight should be taken into account, support an argument that the question of whether light from other quarters should be taken into account is a question of mixed fact and law: is the dominant owner assured of the continued benefit of the light?

An issue arose in the course of argument as to whether the 203 development site and Arbor should be treated as a single servient tenement, or as two or more tenements.

But for the s.203 resolution and the subsequent property transfers, the Claimants would have been able to rely on their rights of light as against LHL and SHL to protect much of the light that they continued to enjoy notwithstanding the construction of Arbor. The land on which Arbor is built is in the same ownership as the rest of the Ludgate House site. There was therefore no difficulty with the Claimants asserting their rights of light in full over the rest of the LHL site. Or, putting the matter in a different way, LHL, as servient owner, was entitled to shift the burden of the rights of light onto the rest of that site by building Arbor as it did.

SHL is a different legal person from LHL, and for that reason, and on account of the apparent separation of the Ludgate House site from the Sampson House site, it would be possible to regard it as being a different servient tenement, over which the Claimants have also acquired rights of light. If that is correct, and if Sheffield Masonic and other cases at first instance decided subsequently were correctly decided, nothing done by LHL, by building on the Ludgate House site, would impact on the burden borne by the Sampson House site. SHL was then not bound to take the whole burden of the rights of light, and the Claimants could not require it to do so.

The Claimants did not really pursue the point that LHL and SHL as owners of the LHL site and the SHL site respectively were two different servient owners. In advancing scenario CS1, the Claimants’ case is that the entirety of the light that will be lost to the 203 development should be left out of the assessment, such that the burden of their rights falls on Arbor alone. They argued, rather, that by seeking and obtaining a s.203 resolution from the local planning authority, SHL and LHL had chosen to treat the Bankside Yards development site as two parcels of land: one, on which Arbor was built, and the other, the 203 development site (part of which is owned by LHL and the other part by SHL). That was justified, they said, because different legal incidents attached to those two parcels from the date of the s.203 transfers.

In my judgment, it is unrealistic, and wrong on the facts of this case, to treat the Bankside Yards development site as if it were two servient tenements in separate ownership. In reality, it is one development site, under single control and ownership. The following points are material:

There being only one servient tenement owned and controlled by BY Jersey, there is no equalisation of the burden of the rights of light (on a Sheffield Masonic basis) required. Scenario CS2 is therefore the wrong basis of comparison to take.

The Powells now accept that there is no actionable infringement of their light in scenario DS1. That means that they have no cause of action unless scenario CS1, which excludes the light from the 203 development site, is the correct scenario to use as the basis of comparison. It is not disputed that the light from where Sampson House and Ludgate House were (although the Powells currently enjoy it) has to be excluded, as the Powells have no right to that light, nor can they expect to continue to enjoy it. The question I have to decide is whether the same approach applies to light from the 203 development site, to which the Powells do have a right and which they are currently enjoying, but which it is very likely that they will lose in the relatively near future.

Mr Cooper claims to be in a different position: he alleges that with Arbor in place and excluding the light coming from where Sampson House and Ludgate House were (scenario DS1), the light to his principal bedroom is actionably infringed. I will decide whether that is correct – it is disputed by the Defendant. If Mr Cooper is right, he has a cause of action regardless of whether CS1 is in principle the right comparison to make. If he is wrong, he stands in the same position as the Powells.

As Mr McGhee emphasised, it is not the case that the Claimants’ rights over the 203 development site have been taken away. They retain them; when a development that falls within the description in the s.203 resolution is built that actionably interferes with their light, their only remedy is damages. They cannot protect their light, which will be lost. But if the s.203 development (or some variant of it) does not proceed as expected, the light will not be lost; the Claimants will then be able to rely on their rights. In those circumstances, the Defendants argue, the light in question should be taken into account.

The Claimants argue that, in view of the reasoning in Smith, the answer is provided by considering the foreseeable practical effect of the s.203 resolution. Although they have rights of light over the 203 development site, there is nothing that they can do to protect the light, which could be taken away by the developer whenever it wishes to build BY5 or BY6, and will be taken away in part by Opus. So – by analogy with light to which they have no right and which cannot be protected – the light to which they have a right but nonetheless cannot protect should not be taken into account.

The Claimants say that that is consistent with the true understanding of the reasons given by Lord Lindley in Colls, and by Romer and Lawrence LJJ in Smith, for considering whether in practice the plaintiff could be deprived of the light in question. They say that LHL and SHL chose to seek a s.203 resolution, and that they should have to live with the consequences of it, which is that the light in question can no longer be protected, and so should be left out of account when assessing the injury caused by Arbor.

The Defendant’s argument is also straightforward. They contend that the way in which the principle in Colls is expressed, as to whether sufficient light remains, does not encompass a case where a claimant has a right of light in relation to light coming in from “other quarters”. There are two conditions for disregarding light that is enjoyed: first, that the claimant has no right to it; and second, that the claimant has not the ability to continue to enjoy it. The question of whether, practically, light from other quarters can be relied upon only arises in a case where the claimant does not have a right to that light. If there is a right to the light, it must be taken into account, until it is lost. Whether the right can be enforced or not, in order to preserve the light, is irrelevant.

The Defendant further argues that if light from the 203 development site is not taken into account, the loss of light resulting from the 203 development will be remedied twice: once by the Court granting an injunction or damages in relation to Arbor (on the basis that the light from the s.203 development site is disregarded), and then again when statutory compensation is triggered by obstruction by the 203 development. The Defendant says that this would be unjust and so the law should not favour such an outcome.

I have not found this an easy point to decide. The particular issue – of an unenforceable right to light – is not addressed in any of the authorities. There is something to be said, in logic or sense, for each side’s approach. The likelihood is (I find) that the light in question will before very long (probably 5-10 years) be lost to the Claimants, despite their rights. (It is not established whether Opus alone will have that effect, and I assume that it will not.) There is no reason to believe that the further stages of the Bankside Yards development will not proceed in due course. On the contrary, it is very likely that they will. In practical terms, therefore, the Claimants are unable to protect their light, any more than they could protect light to which they have no right. Indeed, the loss of the Claimants’ light over the 203 development site is more likely, because of the purpose behind the s.203 resolution. In both cases, others have it in their power to obstruct the light at any time. On the other hand, if there is currently sufficient light because of light from elsewhere to which the Claimants have rights, it can be argued that that light should be taken into account, and that there is no infringement now on the basis of what is likely to happen in 5-10 years’ time.

For the reasons that follow, despite the attractive simplicity of the Defendant’s argument, which was skilfully argued by Mr McGhee, I am ultimately unable to accept it. I consider that the true reason, on the authorities, why light has been left out of account is that the claimant cannot protect it, not simply that the claimant has no right to it.

When determining whether a right to light has been actionably infringed, it is right to take into account other light that the dominant owner enjoys (light “from other quarters”), not just the remaining light from a defendant’s land. There is no infringement if, in fact, the dominant owner will continue to be able to enjoy light from other quarters, in perpetuity, and the light is sufficient – even if the owner has no right to it. But other light that the dominant land actually enjoys will not be taken into account if the owner has no effective means of protecting it, regardless of when the light may be obstructed. In such circumstances, the infringement is actionable when the obstruction is made, or threatened, and not only when the other light is lost. More detailed reasons for this conclusion are set out in the following paragraphs.

First, although Lord Lindley’s words in Colls (at [67] above) are directed to a case where no right to light exists, so that the light could be taken away at any time, the House of Lords was not addressing the much more unusual case where a right to light exists but cannot be enforced. It is, self-evidently, an unusual case where a dominant owner has a right of light but nevertheless is unable to protect it. There had been no such case before 1904, as far as the researches of Counsel have established (though it could theoretically have arisen, e.g. if an Act of Parliament had authorised works that would interfere with light from another quarter, to which the dominant owner had acquired a right). The fact that Lord Lindley considered only the paradigm case in which light could not be protected does not mean that the principled basis for the decision should not apply to a case such as this.

Second, the principle underlying Lord Lindley’s rule, which was applied by Romer and Lawrence LJJ and Maugham J subsequently, namely that light that cannot be legally protected should be left out of account, is more consistent with treating light to which there is a right but which cannot be protected in the same way, rather than taking light that will be lost into account. Whether or not Lord Lindley meant his words “and of which the plaintiff may be deprived at any time” to emphasise the consequences of the preceding words (“light to which a right has not been acquired by grant or prescription”) or be to a second condition, it is clear that they identify, as the relevant concern, the practical consequence of the absence of rights of light.

It is notable that, in addressing the issue of reflected light in its closing submissions, the Defendant summarises the position as follows:

“As a matter of law in assessing whether a reduction of light amounts to an actionable interference, light from other sources is taken into account whether or not there is a right to such light provided only that in practice the dominant owner will not be deprived of that light: Smith v Evangelization Society (Incorporated) Trust [1932] 1 Ch 515 at 539-540 per Romer LJ”.

I agree that that is a fair way of summarising the basis for the decisions in Colls and Smith. The principled basis for assessing whether an interference is actionable should not be different, depending only on the answer to the question whether a right to the other light exists.

If the issue were determined by the answer to that question, Smith would have been decided differently (although an owner can ensure that light passing over his own land is not obstructed, they have not acquired a right to it, by grant or prescription). If it is accepted that the issue is not resolved by asking whether there is a right to the light, there is no reason of principle to treat differently a case where a right to light does exist but the light cannot be protected. The touchstone of the Colls test is whether, despite the loss of light, sufficient light will in fact remain available, on an enduring basis.

Third, as Sheffield Masonic illustrates, having a right to light “from other quarters” does not necessarily mean that all that light can be protected. If the existence of a right to light from elsewhere were a simple answer to the question, that case would have been decided differently. Even if the Defendant is right to argue that Sheffield Masonic was wrongly decided, the approach that the Defendant advocates for such a case (the Thorpe v Brumfitt approach) would lead to the same result, namely that the dominant owner could not expect to protect all the light from the other quarter. It is therefore not a simple answer that a right to light exists.

Fourth, the argument that there is no infringement yet – because there is a right in law to enjoy light from the 203 development site – does not provide a satisfactory result. It seems artificial to take light into account, on the basis that it can be protected by enforcing the right, when the opposite is the case. The Claimants could not obtain an injunction against the developer to restrain interference with that light. Although the Defendant suggested that it is unprecedented to contend that there is a serious infringement of the Claimants’ rights when no building has yet been built on the 203 development site and the light is currently good, the same approach is taken in its DS1 scenario, in relation to light from the former Sampson House and Ludgate House, i.e. it is left out of account, even though it is enjoyed. Positing the presence of the 203 development site buildings in the assessment, when they are not there, is not a subversion of reality, but only a means of leaving out of account light coming from that site when assessing the impact of the loss of light from elsewhere. It is, indeed, commonplace for infringement to be alleged on the basis that light from other quarters, which is currently enjoyed, is at risk of being lost and so should be ignored in the assessment.

Fifth, the approach advocated by the Defendant could leave a dominant owner like the Claimants without an effective remedy for the injury caused by the first obstruction. When the 203 development is built, the dominant owner is entitled to statutory compensation for any diminution in the value of their property caused by the protected development, but not for the contribution to the loss made by the first obstruction. Although, in principle, the dominant owner can, at the later time, allege infringement by the first servient owner to build, by analogy with the reasoning in Thorpe v Brumfitt (see at [72] above), at that time the dominant owner is likely to be unable to assert prescriptive rights of light against that servient owner (unless they have already established those rights by court decision or agreement). A claim under the Prescription Act cannot be made once the actual enjoyment of light over the servient tenement has been interrupted for at least a year.

The Thorpe v Brumfitt analysis works well when various obstructions that together amount to a nuisance occur at about the same time (as on the facts in that case), but much less well when there are years between the events in question. To be sure of protecting a future claim, the dominant owner would have to issue proceedings at a time when there is ex hypothesi no infringement, to protect against the possibility of a later development elsewhere. This would be a strange thing for the law to encourage, as the means of protecting a possible future claim. (Whether an alternative claim based on lost modern grant would be available, at the later time, would depend on other factors, namely whether enjoyment of light had been “as of right” for a period of 20 years, and whether the court was willing to draw an inference that a lost grant must have been made at or before the start of that period.)

Sixth, the countervailing objection to CS1 made by the Defendant, namely that if the first obstruction (Arbor) is actionable compensation will be paid to the Claimants twice over, taking account of the same loss of light, is not sustainable. Even if it did lead to an element of double recovery, that would not necessarily be an objection. Statutory compensation is payable pursuant to a separate statutory code, voluntarily invoked by the Defendant, which can be regarded as the price payable by a developer who seeks its help to override rights that could prevent the development. In any event, it is not apparent that double compensation will be paid to the Claimants, because, as Mr Calland submitted, it is a different injury that is being compensated, namely the interference with the rights of light caused by the 203 development, not the interference caused by Arbor.

The principal remedy sought by the Claimants for the construction of Arbor is an injunction to cut it back, to protect their light. If, as a matter of discretion, an injunction is refused, the Claimants will be awarded either negotiating damages, if appropriate, or damages reflecting the diminution in the value of their property.

If negotiating damages are awarded, in lieu of an injunction, the monetary compensation is for loss of the benefit of being able to enforce their rights. Such damages are not compensation for the same thing as the statutory compensation. There is no objectionable double recovery. The fact that further monetary compensation will come, for the further losses caused by the 203 development, will be one among many arguments raised in the hypothetical negotiations, used to assess negotiating damages. Even so, it does not compensate loss caused by Arbor.

If diminution in value damages are awarded instead, they should reflect only the diminution in value of the flats caused by Arbor, not by the 203 development. The loss of light caused by the 203 development is built into the Before assessment, and it is only the difference between the Before and the After assessments that is compensated in damages, if that additional loss of light is actionable. Further, the damages awarded should take into account that: (a) for the time being, possibly for some years, the light will remain good, so the further injury caused by Arbor will not be felt for some time; and (b) when the remaining good light is actionably infringed, the owner of the flats will be entitled to statutory compensation, which will compensate for loss caused by the 203 development, but not by Arbor. There is therefore no double counting in principle, because the two sets of damages awarded are for different losses.

In response to my questions about the right way to identify the loss and calculate the damages, the Defendant suggested that once the diminution in value at current values has been identified, an appropriate deferment rate should be applied, to reflect the fact that the impact of the infringement will not be suffered until a later time. This was supported by Mr Ingram in his evidence in chief, though it was not a matter that either expert had considered before I raised it during the trial.

Although deferment is a means of quantifying the value today of a sum to be received at a future time, it is an appropriate way of reflecting the fact that the additional adverse effect of the loss of light from Arbor will not be felt for some time. Mr Calland argued that deferment was wrong: that damages awarded as a proportion of current values of the flats will be based on lower figures than the value of the flats when the impact of the 203 development is felt, and so there should be no additional discount. However, it is not possible to speculate about whether, and to what extent, the increase in value of the flats (if any) will exceed the discount rate. Provided only that the current values assume an immediate reduction in light, it is appropriate to determine the diminution in value at current values and then make an allowance for the fact that there are likely to be years of good light before BY5 and BY6 are built. The fact that the discount is not being applied to value a deferred receipt might, however, be a reason for adopting a lower discount rate than the rate than would conventionally be applied for that purpose.

However the calculation is done, the key point is that diminution in value damages payable by the Defendant today are for the harm caused by the additional loss of light attributable to Arbor, not for the loss of light caused by the 203 development. There is therefore no double counting of court-awarded damages and future statutory compensation.

Seventh, if the protected 203 development had been built first and statutory compensation paid, and Arbor (unprotected) then followed, the Before and After analysis for any additional loss of light caused by Arbor would clearly be CS1. This would result in an assessment of the additional impact of the loss of light caused by the building of Arbor alone. It is difficult to see why a different comparison should apply because Arbor is built first and the developer has the right to build out the 203 development later. It is important to note that the Defendant does not argue that the light from the 203 development site should be taken into account because the s.203 resolution came after Arbor was built. Indeed, by advancing the Thorpe v Brumfitt principle as part of its argument, the Defendant implicitly accepts that what is not a nuisance at the time when it is built may become one, when light from other quarters is obstructed later.

Eighth, the Defendant’s argument that scenario DS1 is the right Before and After comparison would enable it to pass the entire burden of the rights of light to the 203 development site, without protection for those rights. The decision in Davis v Marrable is inconsistent with that approach. It illustrates that a servient owner can indeed move the burden to a different part of the servient tenement, but only if the light from that part will be protected. That would not be the case here.

Ninth, although there is no certainty that the 203 development (or a variant of it) will be built, there is equally no certainty that the owner of adjoining land, over which the dominant owner has no rights, will build (and I was told that the adjoining owner in Sheffield Masonic never did raise his house). But in such a case the court acts on the basis that the light is likely to be obstructed at some stage, because it can be. If the court is satisfied, at least, that the protected development is likely to be built (which I am), the same approach should be taken, and the light will be left out of account.

Tenth, the question is not whether the light from the 203 development site can be taken away, as Parliament has decided that it can be, upon payment of compensation: it is whether that light should be taken into account in determining whether other development causes an actionable loss of light.

For these reasons, scenario DS1 is the wrong comparison.

In my judgment, scenario CS2 is also the wrong comparison, first because CS1 is the right analysis, and second because the LHL site and the SHL site fall to be treated as a single servient tenement, not as separate tenements over which different rights of light exist. There is therefore no need to equalise the burden of the rights between tenements in different ownership, in the way that scenario CS2 assumes.

In any event, the Opus site and the rest of the LHL site clearly are a single tenement, in single ownership. It would therefore be inappropriate to equalise the burden as between Arbor and Opus and building BY1.

Further, and in any event, if there was an equalisation called for between Arbor and the 203 development site, or between the LHL site and the SHL site, the Claimants have not gone about it the right way by seeking to equalise the height of all the buildings. In such a scenario, it is the burden that should be equalised, by each of the putative servient tenements contributing an equal part of the necessary light. That will inevitably mean that buildings closer to the Claimants’ flats will have to be lower than buildings further away, as one can readily understand by taking a notional 45 degree angle from the floor levels of the flats extending over the Bankside Yards site. To equalise the height of the buildings on the site means that buildings such as Arbor are bearing a greater share of the burden than buildings BY5 and BY6.

Accordingly, were CS2 in principle the right approach, I would have held that the Before and After assessments were not the right ones in any event, and so do not establish an actionable infringement.

Since the decision that I have reached on the applicability of scenario CS1 is new law, which may well be the subject of an appeal, I will set out (briefly) my conclusions on whether the evidence applied to scenario DS1 shows an actionable infringement in relation to flat 705, after I have done the same exercise on scenario CS1.

As previously stated, the Claimants’ expert light surveyor, Mr Ian Absolon FRICS, provides his opinion that there has been an actionable interference with the Claimants’ light on the basis of the traditional Waldram method of analysis, and he rejects as inapposite and unreliable the assessments produced by the “Radiance” methods and other assessments, on which the Defendant relies.

The Defendant’s expert light surveyor, Mr Gordon Ingram FRICS, ultimately rejects the Waldram method as being inaccurate and outmoded, in favour of an analysis based on other methods, primarily the median daylight illuminance method (“MDI”) but also the median daylight factor (“MDF”). Both of these are contained in a British Standard giving effect to a 2018 European Standard (BS EN 17037:2018), called “Daylight in Buildings” (“the 2018 BS”), which provides standards for the design of new buildings. These assessments are carried out using a computer software package called “Radiance”. The methods do not purport to be a standard for assessing whether interference with rights of light is actionable, but there is obviously considerable overlap between the process of designing buildings to maximise the ingress of daylight and sunlight and the assessment of whether sufficient light exists within a property for ordinary purposes.

In addition, Mr Ingram relies on a report produced in 2022 (3^rd ed.) by the Building Research Establishment, called “Site layout planning for daylight and sunlight” (“the BRE Guidance”), which gives guidance on achieving good daylighting and sunlighting within buildings and in the open spaces around them. It is intended for building designers, owners, consultants and planning officials, and was written to complement the 2018 BS. It is concerned with achieving good daylighting in new buildings and with preserving it in existing buildings nearby, and with optimum site layout.

The BRE Guidance refers to the 2018 BS and contains three additional methods that can be used to inform a (planning) assessment of the impact of new buildings on existing buildings, as well as the design of new buildings: the vertical sky component (“VSC”), which measures the proportion of the total sky illuminance that falls on the mid-point of the exterior of given window of a property; the no sky line (“NSL”), which determines what proportion of a room at a working plane has or will have no direct sky visibility; and the annual probable sunlight hours (“APSL”), which is that proportion of the total number of hours in a year where the sun is expected to shine on cleared ground in the locality that the sun will reach a given window in a building.

Mr Ingram’s conclusion that, even on scenario CS1, Arbor does not amount to a substantial interference with the Claimants’ rights of light, is, he says, the result of taking account of the results produced by all the methods of analysis that are available to him, though he considers that MDI and MDF (in that order) are the ones to be accorded most weight.

This is the first time that detailed evidence and argument on the respective merits of these different methods of assessment have been presented to a court.

There is some common ground on the question of sufficiency of light. The parties agree that:

Furthermore, despite their differences as to the best method of assessment to use, there is substantial common ground between the experts on the results that their analysis has provided, including that:

This degree of common ground is in my view significant. Although the experts differ slightly in the way that they apply the Waldram method and so produce slightly different percentage results, the differences are immaterial to the results, on the CS1 comparison. The Waldram method shows the light to be insufficient by a substantial margin for all three rooms in the After assessment – which is what matters on the question of sufficiency. Further, on the MDF and MDI methods, the principal bedrooms of both flats and the LKD in flat 605 fail to meet the minimum targets in the After assessments.

One might wonder, therefore, how the two experts came to opposite conclusions on the question of whether, on CS1, Arbor makes the light insufficient and is a substantial interference, given that the method favoured by Mr Absolon and the methods favoured by Mr Ingram seem to produce the same results, namely that the remaining light in the three rooms is insufficient (in Waldram parlance) and substandard (in 2018 BS parlance). It is important to recognise that both experts consider that an element of judgement should still be applied to any results, rather than applying them arithmetically to produce the conclusion; and Mr Ingram said that his opinion was an overall evaluative conclusion based on his interpretation of the graphical representations of the results. Nevertheless, given the consistency of the results, there is inevitably a question raised as to whether (and if so on what basis) an evaluative judgement applied to the results can reliably support a conclusion at variance with them all.

Before considering that broad question by reference to Mr Ingram’s evidence, there are some particular issues that can be addressed at the outset, because they are of significance for Mr Ingram’s ultimate conclusion. They are:

In identifying these particular questions, I have not ignored the rest of the (voluminous) expert evidence that the parties have adduced. I have carefully considered all the evidence of Mr Ingram and Mr Absolon, but it is not possible, within the confines of a judgment of reasonable length, to address and try to answer every point that is made.

Subject to the answers to the above 3 initial questions, the following higher level questions will then also be of importance:

Before addressing the 3 initial questions in [126], I should say something more about the expert witnesses on the light issues and about the methods of assessment that they have used.

Both light surveyors are highly experienced and expert, without question. Mr Absolon came to this dispute relatively late, when a previous expert instructed on behalf of the Claimants was forced to withdraw, owing to a perceived conflict. Mr Ingram and his firm, GIA Associates, on the other hand, have been involved with the proposed Bankside Yards development since before the time when Native Land bought the site. He has worked, with another partner of GIA, as the head of a substantial team of surveyors and technicians, advising the developer on strategy and the development, and on how to deal with potential rights of light objections. GIA was also involved in placing evidence before the Council in support of the s.203 application. Mr Ingram told me that he had been in charge of the overall strategy, at high level, but that his partner, Mr Kevin Francis, was the principal surveyor heading the team on the day-to-day work on the project.

Mr Ingram clearly did not feel that his ability to give objective and honest opinions on the question of whether the Defendant has infringed the Claimants’ rights to light was compromised, and Mr Calland did not suggest to him that he was conflicted. Mr Calland did suggest that, when it came to the basis on which Mr Ingram had carried out his assessments, he had made adjustments to measurements, or excluded certain areas of the rooms, in “an attempt to push every variable you can push in order to change the results to make them look better for your client”. Mr Ingram denied that absolutely.

Both light surveyors assisted me to understand the matters in dispute, though, perhaps inevitably, each ultimately contended for a conclusion that was in favour of the party who had appointed him. There were areas in relation to the evidence of each where I was concerned that a fair approach to the evidence might not have been taken. I accept that, within the confines of the exercise, each believed what he told me. That does not mean that I agree with the judgements that they made.

Mr Absolon, it can be said, was more of an “old school” surveyor, sticking to traditional methods and having a sceptical view of other methods that were not designed to assess whether the light in a room was “sufficient … according to the ordinary notions of mankind for the comfortable use and enjoyment of [the] home as a dwelling-house”, which is the relevant legal test. He accepted that there was scope for methods like MDI and MDF to be used in future to provide a better assessment than the traditional Waldram assessment, because of the more sophisticated computerised data that they can use, but considered that further testing and calibration was needed before they could provide a more reliable indication of sufficiency of light than the Waldram method. He accepted that an expert eye was needed to make the final determination, in a borderline case, based on where the 2% sky factor contour lies within the room in the Before and After assessments, and taking into account any peculiarities in the shape or size of the room or unusually large windows.

He accepted that this would normally require a consideration of the contour lines, particularly to address a question of whether any change would be noticeable or amount to a substantial interference. It emerged that, in fact, Mr Absolon had not produced the necessary diagrams with contour lines to demonstrate the change from the 203 development with cut back Arbor (Before) to the 203 development with Arbor as built (After) (the parties referred to this as the CS1.B1 v CS1.A analysis, but I will refer to it as the “cut back Arbor analysis”), only the diagrams that showed the movement in the contour from the 203 development without Arbor (Before) to the 203 development with Arbor as built (After). While this does not affect the position of the After contour line, it does affect the position of the Before contour line and therefore the degree of movement and the impact on the room resulting from the obstruction.

Mr Absolon, when challenged about this, said that with years of experience he could do the same exercise satisfactorily from the arithmetical results. I was not persuaded by that in any marginal case, though I accept that he has great experience. Such changing contour lines are regularly produced in diagrammatic form, rather than just as results, because they aid understanding of the impact of the change. Mr Absolon’s appreciation of the impact of the change in the cut back Arbor analysis was therefore likely to have been coloured by the difference between no Arbor and Arbor as built, which would show a greater change. Accordingly, where there is doubt about the result, I will exercise some caution in placing reliance on what Mr Absolon said about the noticeability of the change in light.

Ultimately, however, I felt that Mr Absolon was simply advocating the use of the traditional Waldram method, on the basis that no better method had been proved to be reliable, and that the answer to the question of sufficiency or insufficiency was produced by the results themselves, subject only to a few additional considerations (which did not apply in this case), and with the answer to the question of substantial effect on use and enjoyment being self-evident from the figures.

Mr Ingram had a more modern approach, which was based on a combination of concern at the limitations of the Waldram analysis and wishing to embrace the more sophisticated analysis that the MDI and MDF offered. He said that this provided a more informed conclusion on the effect of any light loss. He could see no reason why these analyses could not be applied directly to the question of sufficiency of the remaining light, though he agreed that none of them is intended to replace, or prove satisfaction of, the legal requirement for sufficient light for ordinary uses. He said that, for him, “the right question to ask is: does this method actually tell me the real effect of the light in [the] space such that I can understand how this space can be used and enjoyed”. That seemed to me to conflate the two separate questions (as the Defendant identified them) of sufficiency of the remaining light, on the one hand, and whether the injury had a substantial effect on enjoyment, on the other.

Mr Ingram accepted that Waldram was a good starting point, and continued to be used by the industry as the standard approach, but that ultimately, once a case was disputed and a detailed MDF or MDI analysis had been undertaken, that would provide a more reliable assessment of whether light within a room was sufficient for ordinary purposes. He accepted that the results produced do not simply speak for themselves, not least because there are different tests that he used, the results of which did not fully align; and that expert judgement was required in order to make the final evaluation about sufficiency of the remaining light, and noticeability of the change, and so whether there was a substantial impact.

Mr Ingram’s knowledge of his subject and understanding of the complexities of the science were very impressive. He was a very fluent witness who was able to explain his answers to questions at length, and persuasively. My impression was that he used the various methods of assessment as providing pieces of information, and rejected the Waldram results in favour of some of the information (but not all) provided by the Radiance results and the assessments from the BRE Guidance. His conclusion was that the reduction in light did not leave the rooms in question with insufficient light for their ordinary use, because of where the main losses of light were experienced within the rooms, and that the reductions would either not be noticeable, or fell in areas where the loss did not matter, so that they did not have a substantial impact. For these conclusions, he relied substantially on falsecolour images produced by the Radiance software, which show, in different shades of colour, the different proportions of unobstructed external illumination (in the MDF method) and the different levels of actual illumination in lux (for the MDI method). He said that these images could only be interpreted by an expert, and that with his expertise the results were tolerably clear.

Ultimately, despite Mr Ingram’s evidence that he looked at all the methods and they all helped to inform his overall judgment “by understanding as many elements around the light as I can”, I consider that his conclusions are based on: a rejection of the Waldram method and results; use of selected results from other methods of analysis; and, most significantly, a subjective interpretation of the falsecolour images produced by Radiance from the MDF and MDI results, which he said justified his views. So, as one illustration only, he accepted that his MDF result for the principal bedroom in flat 605 was a “fail” but said that, bearing in mind the falsecolour images, the impact was not substantially adverse.

The Waldram method is not a measurement of light as such, but a measurement of the degree of exposure of a room to the sky. It takes exposure to at least 0.2% of the notionally unobstructed sky dome in half of the internal area of the room at a working plane (85 cm) as a proxy for sufficiency of light within the room as a whole. Waldram decided on the 0.2% sky factor at working plane based on his assessment of the amount of light on a uniformly overcast day that would be needed for ordinary use of the room, and referred to the 0.2% sky factor line as a “grumble line”, beyond which an ordinary person would be liable to complain about the inadequacy of the light. The judgment was that a room that was at least half lit to that modest level on a uniformly grey day would be adequately lit overall. Of course, the 0.2% sky factor line may mean that there are parts of a room that are very well lit (closest to the windows), where much more than 0.2% sky is visible, and parts that are very poorly lit. Subsequent studies indicate that the level of light from the sky that Waldram identified is likely to be exceeded in fact on more than 80% of the days in the year, so, as is now accepted, Waldram’s measure was very low. It was not an attempt to capture an average measurement of light, but rather a low measure that, if achieved on a uniformly overcast day, would mean that in overall terms the room would be sufficiently lit.

The method is applied to each aperture through which the sky is visible, but any partial blockages of light caused by the window frames, glazing bars and furniture are disregarded. Waldram considered that the loss of light through the glass and frame and the benefit of reflected light coming into the room other than directly from the sky were likely approximately to cancel each other out, and so he was content to take the sky visibility factor as the sole proxy for the level of illumination in the room.

The method calls for a 0.2% sky factor line to be plotted on a plan of the room (representing the working plane), both in the Before and the After scenarios. If 50% or more of the room is on the window side of the line (in a simple case where only one wall has windows), the room is sufficiently lit. If less than 50%, it is insufficiently lit. The Before and After lines enable one to see exactly where the relatively “good” light will be lost in the After scenario, and how much is lost, which is used both as an indication of how the impact of the loss of light will be felt and as a basis for valuing the well-lit area that will be lost, if the obstruction remains. Where infringement is established by this method, by reverse engineering it is possible to identify the cut backs that would be needed to the obstruction to leave exactly half of the room exposed to 0.2% sky factor.

The results of the Waldram method are expressed as a percentage, with anything 50.00% or over indicating that the room as a whole is “well lit”, so that, if all that remaining light can be protected, there is no actionable interference with light.

The VSC (vertical sky component), referred to at [119] above, measures the proportion of the entire visible sky dome falling on the centre point of the exterior of a window. It is not a measure of light within the room, but rather a measure of the degree to which a primary source of light falls on the exterior of the building. The BRE Guide says that 40% is a maximum, in reality, for a window in an unobstructed vertical wall, and that any proportion in excess of 27% is likely to be sufficient, subject to other parameters. It recommends that a reduction to below 27% be avoided:

“If the VSC, with the new development in place, is both less than 27% and less than 0.80 times its former value, occupants of the existing building will notice the reduction in the amount of skylight.”

The implication is therefore that if the reduction is less than 20%, the occupants may not notice it.

The NSL (no sky line) speaks for itself and is the equivalent (at 0.0%) of the Waldram 0.2% sky factor. The BRE Guide advises that if more than 20% of the room lies beyond the NSL, supplementary electric lighting will be needed. If, following new development, the area of the existing room with sky visibility is reduced to less than 0.80 times its former area:

“this will be noticeable to the occupants, and more of the room will appear poorly lit. This is also true if beyond the no sky line encroaches on key areas like kitchen sinks and worktops”.

The APSL is a measure of the proportion of expected sunlight that will fall on a window. It is a measure of exposure to the sun, not daylight or light from the sky. The BRE Guide advises that one quarter of all sunlit hours is likely to be sufficient, if it includes at least 5% of the hours between 21 September and 21 March in each year. If the overall annual loss resulting from new development is less than 4%, this is said to be a small reduction.

“Any reduction in sunlight access below these levels should be kept to a minimum. If the available sunlight hours are both less than the amount above and less than 0.80 times their former value, either over the whole year or just in the winter months..., and the overall annual loss is greater than 4% of APSH, then the occupants of the existing building will notice the loss of sunlight...”

Again, the implication is that a reduction of less than 20% may not be noticed.

MDF is the proportion of the applicable total illuminance from the unobstructed CIE overcast model of the sky dome that is exceeded for more than half of all the daylight hours in the year in more than half of the defined area of a room at the reference plane (a working plane equivalent to the Waldram working plane). It therefore involves taking a median figure for illuminance at a median point in a room and expressing that as a proportion of the available total illuminance. 0.7% of the total available is considered to be the minimum for a bedroom in the UK (equating to 100 lux), 1.1% for a living room, and 1.4% for a kitchen. Unlike the Waldram method, MDF takes into account indirect illuminance from external and internal reflectance.

MDI adds to the MDF analysis climate-based daylight modelling, in place of the CIE overcast sky model, and takes into account predicted weather for each daylight hour for the location from computerised weather files, so that MDI uses the predicted average actual illumination in the room. The measurement is taken at the median hour in terms of level of illumination and is the level that will be achieved at half the grid points in the room. As with MDF, not all the internal area of the room is taken into account. This is a “highly accurate and reality-based daylight assessment, based on orientation [of the room]”, as described by Mr Ingram. The target set by the 2018 BS is 100 lux for a bedroom, 150 lux for a living room and 200 lux for a kitchen. Mr Ingram accepted that those targets, even if achieved, may not give a predominantly daylit appearance in a room, as they are below the minimum standard specified in the EU standard.

Both MDF and MDI require assumptions to be made about the levels of reflectance that should be taken into account, depending on the external environment and the internal finishes of the dwelling. In the event, the expert witnesses were able to agree most of these factors for reflectance, except for the surface of the external terrace and parapet wall. Mr Ingram adopted a reflectance factor of 0.4 for the wall and 0.3 for the terrace, whereas Mr Absolon used the default factor of 0.2 for both. The methods also require allowances for the loss of light through glazing and window frames, which may differ depending on the angle at which the light primarily strikes the external window and the nature of the glazing: single, double or secondary.

The Waldram method has accumulated no particular guidance about how a room such as an LKD should be treated, or whether it should be analysed differently. The right approach is therefore to apply the Waldram method to it, but then, in considering as an expert the pattern of results produced, consider whether, by virtue of the unusual shape or depth of the room or for other distinct reasons, the result should not lead to the conclusion about sufficiency or insufficiency of light that it appears to indicate.

So far as the Radiance and BRE Guidance methods are concerned, the National (UK) Annex to the 2018 BS states as follows, in relation to the MDI method:

“Where one room in a UK dwelling serves more than a single purpose, the UK committee recommends that the target illuminance is that for the room type with the highest value – for example, in a space that combines a living room with a kitchen the target illuminance is recommended to be 200 lx.”

That figure is based on the table NA.1 of values of target illuminance for room types in UK dwellings, which specifies 100 lux for a bedroom, 150 lux for a living room and 200 lux for a kitchen – the targets that are used in the MDI method.

The BRE Guidance states, at paras 2.1.14 and 2.1.15:

“Living rooms and kitchens need more daylight than bedrooms, so where there is the choice it is best to site the living room or kitchen away from obstructions.

…..

Non-daylit internal kitchens should be avoided wherever possible, especially if the kitchen is used as a dining area too. Daylight levels in kitchen areas should be checked. If the layout means that a small internal kitchen is inevitable, it should be directly linked to a well daylit room. Further guidance for assessment of this situation is given in Appendix C.

Appendix C at C.17 relevantly provides:

“Where a room has a shared use, the highest target should apply. For example in a bed sitting room in student accommodation, the value for a living room should be used if students would often spend time in their rooms during the day. Local authorities could use discretion here. For example, the target for a living room could be used for a combined living/dining/kitchen if the kitchens are not treated as habitable spaces, as it may avoid small separate kitchens in a design. The kitchen space would still need to be included in the assessment area (Figures C4 and C5).

Figure C4 shows a combined LKD area and has the following commentary:

“for a combined living/dining/kitchen area, the kitchen should always be included as part of the room area in the calculations, even in cases where the kitchen is deemed non-habitable and the living room criterion is applied to the whole space.”

It follows that the guidance is firmly against excluding the kitchen space of an LKD, or treating it as a separate room, but with discretion to apply the living room lighting target rather than the kitchen target, if the kitchen area is non-habitable.

Mr Ingram has treated not just the non-habitable kitchen worktop spaces but also the floorspace in between them, and the space leading up to the fridge/freezer – amounting in aggregate to about a quarter of the total area of the LKD – as a notionally separate kitchen area, attracting the highest 200 lux requirement.

His evidence in his expert report about this was as follows:

“4.13

… Urban flats are often designed to position the kitchen in the darkest part of the room (i.e at the rear). This configuration, unsurprisingly, exists in both flats. ….

4.14

The expectation of natural light for a kitchen in this configuration will clearly be significantly lower and will not meet national industry guidance which places a higher requirement of natural light. This guidance is applicable to cases where a kitchen is a separate and main habitable room. It does not apply to the configuration common in flats such as these where the kitchen is placed at the back of and in the darkest part of a room which includes a living and dining area. Given that the kitchen is a separate and distinct area of the living/dining/kitchen space and this area will be confined to food preparation and the like, I consider that it is appropriate to consider the kitchen area separate from the living/dining area when assessing the reduction in and sufficiency of light within these spaces.”

Mr Absolon stated in his supplementary report, at para 3.54, that he does not agree with Mr Ingram’s treatment of the kitchen. He was asked in cross-examination if the kitchen arrangement was the only realistic way of placing the kitchen in the room and he disagreed and said that he had seen lots of different versions of how LKDs were arranged. The LKD might not have an island unit and the units might be on the adjacent wall, so the room had to be assessed on its full potential for use. He said “you can’t just lob out a piece of the room and decide that it doesn’t count. It just skews the figures” (at this point, Mr Absolon had been asked about excluding circulation and wardrobe space from the bedrooms, but his point was a general one).

In the first and each subsequent joint statement of the experts, there is recorded a view of Mr Ingram that the flat 605 kitchen is at the rear of what is in overall terms a deep room, and that he believes that kitchens in modern flats were designed primarily to rely upon artificial lighting compared with natural daylight. The last joint statement also contains a plan that illustrates the different approach taken by the experts when assessing the LKD as a whole – which raises different questions.

Asked about the BRE Guidance about bedsits and LKDs, Mr Ingram said that the guidance was intended to give local planning authorities sufficient discretion so that dwellings were not poorly designed, just so that minimum targets of illuminance could be achieved. He said that most local authorities recognise that with LKDs it is the living space that is predominantly the most relevant use, and are prepared to work with a target of 150 lux for such a room. Mr Ingram also acknowledged that, today, there is a possibility of adults sharing flats and using bedrooms as working space as well as sleeping space.

Mr Ingram explained that he took the height of the working plane for the kitchen worktops and island unit as 93 cm rather than the standard 85 cm, to reflect reality, but accepted that the effect of that was that less of the island unit would fall within the 0.2% sky line than would be the case if he had taken 85 cm.

As to the LKD, based on the Waldram analysis results alone, Mr Ingram accepted that they showed that the LKD was less suitable for the purposes to which it would be put, and not as beneficial an environment for carrying out the ordinary activities of everyday living – subject to the qualification that he did not accept that Waldram correctly reflected the position. He was willing to say that, based on the 45% to 46% result on Waldram (depending on which expert’s approach was used) in relation to the LKD:

“… you would be in a scenario saying: that’s interesting, that’s getting to a debatable point, if Waldram was right.”

I reject Mr Ingram’s case that it is appropriate, when considering whether a reduction of light to an LKD leaves insufficient light or causes a substantial interference, to treat the kitchen as a separate room. None of the BRE guidance suggests that that is appropriate, and there is no precedent for it when applying the Waldram method. What may be justified, as the BRE Guidance describes, is to use the lower target of 150 lux for the whole room, rather than a target of 200 lux driven by the presence of the kitchen. However, Mr Ingram did not do that: he applied the lower target of 150 lux but only after excluding the kitchen altogether from the LKD, leaving only the best lit three-quarters of the room to be assessed as an LD. Assessed as a separate room, the kitchen is already a conspicuous fail in the Before assessment, and the After assessment only makes a bad position slightly worse. The fact that it may be appropriate when designing new flats to leave a kitchen area out of the analysis, by designating it as non-living space, to avoid distorting the design for a living room, does not mean that, when answering the question whether there has been an actionable interference with light to an existing room, that room should notionally be treated as excluding part of the space.

If the LKD is treated as a single room, it falls significantly below the minimum standard for both MDI and MDF. At that point, Mr Ingram sought to rely on the fact that the reduction in light would not be noticeable, as it is a reduction of less than 20% of the former value. I deal with this issue separately, below.

Applying the analysis of the LKD as a single room, there was a significant failure to achieve the 50% measure on the Waldram analysis and a failure on the MDF/MDI analysis.

The bedroom in flat 605 will have insufficient light, according to both expert light surveyors. On the Waldram method, Mr Absolon measures a reduction from 53.53% to 33.73% and Mr Ingram from 55.89% to 35.25%. The differences result from the different treatment of small areas of the bedroom currently used for a dressing table and a wardrobe, but they do not matter for this purpose.

On the MDF method applied by Mr Ingram, the bedroom reduces from 0.7% of the full sky illuminance to 0.5%, which is below the 0.7% minimum target for bedrooms. Mr Absolon also carried out an MDF assessment, in his supplementary report, and his results are somewhat different and differently expressed (as a percentage of the room that does achieve 0.7% - namely 28.5% rather than the target of 50%) but the conclusion is the same, namely that the MDF target minimum illuminance level will not be achieved.

On the MDI method applied by Mr Ingram, the bedroom in flat 605 achieved a healthy 149 lux in the Before scenario, well ahead of the minimum standard of 100 lux, but in the After scenario only achieved 97 lux, being a narrow “fail”. On Mr Absolon’s measurements, the Before result was 135.4 lux and the After result 85.9 lux: a more significant fail.

The bedroom in flat 705 will have insufficient light according to both experts. On the Waldram method, Mr Absolon measures a reduction from 38.29% to 28.85% and Mr Ingram from 47.77% to 35.44%. In both cases, the light was insufficient to start with and has become significantly worse. The differences in their results are attributable to quite significant areas of the bedroom that Mr Ingram excludes, namely the built-in wardrobe space and area around the door and leading to the en-suite bathroom (which are the areas of the room with the least good light), but these differences do not affect the Waldram results other than the extent of the failure.

On the MDF method, applied by Mr Ingram, the bedroom reduces from 0.6% of the full sky illuminance to 0.5%, which is below the 0.7% minimum target for bedrooms. Mr Absolon’s MDF After assessment records 16.9% of the room rather than the target of 50% as achieving the minimum level of 100 lux, down from only 18.8% in the Before assessment, but the overall conclusion is the same.

On the MDI method, applied by Mr Ingram, the bedroom achieved a “pass” at 125 lux in the Before scenario, above the minimum standard of 100 lux, but in the After scenario only achieved 95 lux, being a narrow “fail”. On Mr Absolon’s measurements, the Before result was 70.2 lux and the After result 52.2 lux: a much more significant fail (which I explain below, in [178]).

Considered simply as results, the Waldram method, the MDF method and the MDI method all suggest that the two bedrooms will have insufficient light. The Defendant’s position is that some of Radiance method failures are marginal and so of much less significance. Mr Ingram said that one would not notice at all the difference between 100 lux and 97 lux. In particular, Mr Ingram notes and the Defendant asserts that on the (preferred) MDI method, the After assessment is only just below the minimum of 100 lux in both cases. Further, he said, the reduction in light is in some instances less than 20%, which is the threshold for noticeability referred to in the BRE guidance on the separate VSC, NSL and APSL tests. Mr Ingram said that he accepted that the 0.5% was a fail –

“[b]ut against where it was, the 0.7%, and that’s why I used the false colour images as well, my view is that I do not consider that to be substantially adverse to use and enjoyment.”

Mr McGhee took Mr Absolon through the relevant figures at the end of his cross-examination, and for this purpose he asked Mr Absolon to look at a different Before assessment, the “cut back Arbor” assessment (on a Waldram analysis), and to compare that with the Arbor as built After assessment. As previously explained, this was because, if one is considering what infringement would be noticeable to the Claimants, it was agreed that the starting point had to be what the developer could lawfully build without infringing the Claimants’ rights, not what the Claimants had actually enjoyed previously.

The right comparison established that, on Mr Ingram’s measurements:

Mr McGhee did the same exercise with Mr Ingram’s MDF and MDI measurements for the LKD in flat 605, which showed a 12.5% reduction on the MDF analysis and a 12% reduction on the MDI analysis.

The Defendant accordingly argued, first, that the MDI assessment failures of each bedroom are marginal in absolute terms, in that they are only a little below the target of 100 lux; and second, that on the MDF results, the reduction in light from the amount that the developer of Arbor could lawfully leave them with is at a level – applying the BRE Guidance on separate methods of assessment – that would not be noticeable, and so cannot be a substantial interference with their light. It is notable, however, that the same arguments cannot be applied the other way round: the MDF failure is not marginal and the reduction in light on an MDI analysis is greater than 20%, in each case for both flats.

As for the margin of failure, the answer to this, so far as sufficiency of illuminance is concerned, is in my judgment that the minimum target level approved in the British Standard version of the EU standard does not allow this kind of marginal failure. In the EU version, the level of 100 lux is a minimum level of illuminance for a bedroom that is required to be achieved for 95% of the assessed space in the room – i.e. only 5% of the assessed area can fall below it. The target for 50% of the space in the EU standard is 300 lux, with the minimum level of 100 lux being deemed acceptable for the remaining, darker 45% of the room. But the 2018 BS version has significantly watered down the EU standard, by requiring the best lit 50% of the room to achieve only the minimum level of 100 lux. There is therefore, in principle, no scope for an argument that something less than the minimum level for 50% of the room is sufficient. The BRE Guidance itself notes that even achieving the minimum standard may not make the room suitable for the elderly. Mr Ingram thought that the “ordinary notions of mankind” were not to be equated with the elderly; but unsuitability for the elderly is an indication that the minimum target does not have leeway built into it.

Another reason why the targets should be regarded as minima, in this case at least, is that the assessment is traditionally done by excluding certain areas of the room that are less likely to be used. This is a border of 300mm around the extremity of the room, so that the assessment grid for MDF and MDI does not take account of the illuminance of this area. The borders on 3 of the 4 sides of a room are generally likely to be less well lit by daylight, as all the examples in evidence demonstrate. The border on the fourth side, where the windows are, is likely to be better lit. Fixing the assessment grid in this way is standard practice, for the MDI and MDF methods, but its consequences for smaller rooms are stark. Omitting a band of 300mm around a room that is 3m by 3m, the size of a small double bedroom, means that only 64% of the room constitutes the assessment grid. This in turn means that the minimum target of 100 lux only has to be satisfied by 32% of the room, rather than 50% (in the 2018 BS) or 95% (in the EU Standard). In a room 4m by 4m, the equivalent figure is 36%. Mr Ingram agreed that the bedrooms in flats 605 and 705 were of these approximate sizes, but felt that this was just one factor among many that was considered when devising the methodology, and so it could not be considered in isolation.

I bear in mind also that Mr Absolon’s measurement was 85.9 lux for flat 605, which was measured on a slightly different basis from Mr Ingram, but which suggests that Mr Ingram’s result of 97 lux might be seen as a maximum achievable result, depending on judgments about what areas of the room it was appropriate to exclude from the assessment, and on whether standard values or bespoke values should be used for some of the reflectances that need to be taken into account. There was also the question of an additional allowance for the secondary glazing that Mr and Mrs Powell had recently installed in flat 605 to attenuate the noise from the railway – which is illustrative of the way that the flat might reasonably be used by an occupier, even though the works were done too late for the experts to take the extra loss of light into account in their results. The difference between the two experts in these respects applied to the configuration of flat 705 produced a much greater divergence of results, 95 lux as against 52.2 lux, and if an area behind the door is included, which Mr Ingram eventually conceded was probably correct, Mr Ingram’s own MDI score goes down to 90 lux, which is certainly not a narrow failure.

In short, given the way that the 2018 BS is calibrated, I do not accept that there is scope for saying that a shortfall of 3-5 lux is of no significance, and that results of 97 and 95 lux are to be treated as being as good as achieving the minimum standard. Or, put another way, they are not a sound foundation for arguing that the results produced by the Waldram method are clearly wrong, or that the light left in the rooms is sufficient – especially when the MDF method results clearly show that it is not.

The MDI method is, in principle, Mr Ingram’s preferred method. I can understand why, and accept his reasons: it is by far the most sophisticated method, and it purports to measure the actual levels of diffuse illumination in a room, using complex data and technology. It is odd, in those circumstances, therefore, for Mr Ingram, faced with his own MDI results that show that a median assessment of the light is substandard, readily to divert from the conclusion to which those results point, and prefer the results of a relatively less sophisticated method, or a subjective appraisal of what is shown on falsecolour images. If it is the sophisticated technology and modern methodology that justifies saying that Waldram is outmoded, more weight should be given to the results produced by MDI; otherwise, an established, widely-used objective standard (Waldram) is being supplanted by subjective interpretation of falsecolour graphics.

As noted above, this question does not arise in respect of the MDI assessments for each bedroom, which both exceed a reduction of 20%. So according to Mr Ingram’s application of the MDI method and BRE tests, the reduction of light in both bedrooms would be noticeable. It is only in relation to the MDF results where the 20% criterion enables Mr Ingram to say that the reduction would not be noticeable.

The criterion of 20% is taken from the BRE Guidance relating to the application of the VSC, NSL and APSH assessments, as explained above ([145]-[147]). The MDF and MDI assessments do not themselves include any such test or qualification, in the way that these other assessments do. Neither does the Appendix to the BRE Guidance that deals with interior daylighting recommendations include such a reference. The EU Standard and the 2018 BS do not include any reference to a margin of non-noticeability: this is unsurprising, as they are concerned with the designs of new buildings optimising the use of light, to ensure that certain minimum standards are always achieved. In the Criteria for Daylight Provision section of the EU Standard, para 5.1.2 states:

“A space is considered to provide adequate daylight if a target illuminance level is achieved across a fraction of the reference plane within a space for at least half the daylight hours. In addition, for spaces with vertical or inclined daylight openings, a minimum target illuminance level is also to be achieved across the reference plane.”

The relevant targets in the ES are 300 lux across 50% of the space and 100 lux across 95% of the space. These are absolute levels, and the latter a minimum target. The 2018 BS significantly reduced the target to 100 lux across 50% of the space.

The Defendant’s case is nevertheless that a reduction in light to a level where it is substandard cannot be a substantial interference unless it is noticeable, and Mr Ingram seeks to rely in this regard on the criterion of 20% reduction in the BRE Guidance.

The VSC, NSL and APSH tests have their limitations, as Mr Ingram acknowledged. He said that the VSC test was “not no help but of limited help”, because it was not picking up what is happening internally in the room. It was a bit of common sense, he said, but useful as a test of noticeability. As for NSL, He accepted that this was essentially the same as the Waldram test, except that it was identifying a simple line rather than a standard: a rough and ready common sense approach, but the 20% noticeability test could not, he accepted, be read across to percentage reductions in results produced by the Waldram method. APSH is a measure of sunlight availability on the outside of the room, not an internal measure of illuminance.

If, as Mr Ingram accepts, the 20% reduction cannot be read across to the Waldram analysis to import an assessment of noticeability, I am not clear why it can be superimposed on the Radiance assessments, as Mr Ingram sought to do. These assessments are a measure of the sufficiency of light in a room, not of whether a reduction in light is noticeable. Whether a reduction of exposure of the exterior of a window to the sky or the amount of sunlight is noticeable is not the same question as whether a reduction of internal illumination is substantial.

Mr Absolon said that the 20% “rule” derived from the BRE Guidance is a blunt instrument, because it depends on what the starting point is; it does not really reflect what happens in rights of light matters, but that it was a useful test in a planning context. He did not agree that it was a useful test in the context of the MDF and MDI methods, and considered that the absolute figures produced by the results were more important.

While accepting, therefore, Mr Ingram’s view that these three BRE assessments provide further information which is of some interest and use to an expert, they do not provide information which is directly applicable to an attempt to answer the question whether internal illuminance is sufficient, or whether a reduction in levels of internal illuminance would be a substantial interference with a person’s ordinary use and enjoyment of property. Given that the measure of 20% is not explained or justified in the BRE Guidance, it cannot be transposed and applied when seeking to answer a different question, in my judgment.

In any event, I am not persuaded that a reduction of the proportion of a room with at least 2% sky factor from 55% to 45%, or a reduction in the median level of illuminance from 110 lux to 90 lux will not be noticeable, though the reduction is less than 20%. If the light is insufficient (or substandard) to that extent, it will very likely have a substantial impact on the use and enjoyment of the room for ordinary purposes.

What is accepted is that where the amount of light is already insufficient and is then further reduced, there is a rule of thumb that a further reduction of up to 2% may not be noticeable. There is no authority that suggests that there is otherwise a test of noticeability when using the Waldram method.

Mr McGhee accepted that in law there was no separate test of noticeability, and that the only two questions were the sufficiency of the remaining light and whether there is a substantial impact on use and enjoyment.

I am unpersuaded by Mr Ingram that the results for the bedrooms in flats 605 and 705 can be said to demonstrate that there is no substantial impact on the basis either that the reduction in the MDF scores is less than 20% or that the MDI scores are almost a “pass”. There is a significant element of cherry picking of results here that is unconvincing. Nowhere does Mr Ingram grapple with the fact that neither the MDI results nor the Waldram results, which show a greater than 20% reduction of light, support the interpretation he seeks to place on the MDF results; nor are the MDI near misses supported by the MDF results or the Waldram results, which show that the targets are missed by a considerable margin (28%, using Mr McGhee’s approach).

The MDI results obtained by Mr Ingram do not justify a conclusion that the light is sufficient or that there has been no substantial impact on the use and enjoyment, on the basis that they are nearly “passes”. For the conclusion that there is no substantial impact, Mr Ingram ultimately relies on his reading of the false colour images.

Having established that Mr Ingram’s conclusions are not supported by the results obtained from the MDI and MDF methods that he has used, nor from his Waldram analysis, there is an overall assessment needed of whether the evidence establishes that the remaining light in the Claimants’ flats will be insufficient or substandard, and if so whether the reduced light amounts to a substantial interference, so as to be actionable.

Mr Absolon’s position is that the Waldram results speak for themselves, so far as insufficiency of light is concerned, and that by using his expert judgement obtained from many years in practice, it is clear that the reductions in light will have a substantial effect on the use and enjoyment of each flat. Mr Absolon does not rely on the Radiance methods or the VSC, NSL or APSH tests in the BRE Guidance, on the basis that they are not directed at assessing the impact of reduction of light on rights of light and do not therefore assist him. In particular, he contends that the false colour images on which Mr Ingram relies are too imprecise, and on the wrong scale, to be able to support a reliable judgment.

Mr Ingram’s approach is, he says, to take all the information produced by the various methods (including Waldram) into account and form a fully-informed judgment as to sufficiency of light and substantial impact on use and enjoyment. He said that each of the methods or tests contributes something to his assessment, and that the MDF and MDI results are the most relevant, both the numerical results and the false colour images of the way that the light falls within the room (expert report, paras 3.107-3.110).

Mr McGhee commended as “exemplary” Mr Ingram’s approach in his summary of technical assessments (which he does as a separate section in his expert report for each scenario for each flat). Mr McGhee suggested that I could take paras 6.4 – 6.46 of the report as a working example of the approach, even though it addresses a comparison for flat 605 between the simple Before and After models, rather than between cut back Arbor Before and Arbor as built After

Each such section in Mr Ingram’s expert report is set out after several pages of results of applying the various methods to the particular scenario, including Waldram diagrams and false colour images accompanying the Radiance results. Mr Ingram provides commentary on each room, but with the LK and kitchen as separate rooms, rather than the LKD as a single room. For each room considered, he summarises what he says the MDF and MDI results show, expressing his view on whether, in light of the false colour images, the reduction in light will be noticeable. He then states, briefly, whether under the VSL, NSL and APSH tests the reductions would be considered noticeable or material. Where one or more test result suggests non-noticeability, Mr Ingram says that it supports his assessment of the false colour images. If one does not, he rejects its result and prefers the Radiance methods:

“Against the BRE Guidelines tests (VSC/PSH) the reductions would be considered non-material and not noticeable, with the exception of the NSL test which indicates there may be a noticeable reduction in daylight. However in my opinion, the more complex methodologies mentioned above actually demonstrate that even this reduction will not be noticeable.”

Mr Ingram then summarises the result of the Waldram analysis, describing it in all cases as “far less accurate”, and where the result is adverse, he comments in terms such as the following:

“… the assessment suggests that the light remaining will be insufficient on the basis that the room has been reduced to less than 50% well lit. There are numerous deficiencies with the Waldram analysis, as detailed above, and in view of the results of the other methodologies considered above, I am clear that the level of light, nevertheless, remained sufficient.”

Each section of commentary on a room in flat 605 ends with a summary. For example, the principal bedroom is summarised as follows:

“I am clear that this room will not only retain sufficient daylight but also there will be no noticeable reduction to it. When sunlight is considered, there may be a noticeable reduction, but the APSH test referenced in the BRE Guidelines, indicates that this reduction would not be materially adverse. Given the use of this room as a bedroom, it is my view that no substantial interference on the use and enjoyment will occur between the “before” and “after” condition.”

At that stage of Mr Ingram’s analysis, the bedroom did “pass” the MDF test, though it failed the other tests – but by the time of the final joint statement, to which the parties’ analysis based on the 2025 consent was annexed, the bedroom was also a “fail”, so that it “failed” the Waldram, MDF and MDI assessments. Mr Ingram did not, however, qualify his overall conclusion, which was that the light was sufficient and that there was no noticeable reduction.

In effect, therefore, Mr Ingram starts with his assessment of the false colour images, and even in a case where the MDF or MDI assessments (or both) show substandard results, gives his opinion that they show that there is sufficient light, or that any reduction is not noticeable or not substantial, then points out any results from the BRE Guidance that support that conclusion, and rejects the Waldram analysis as being wrong, or deficient. This leads to an overall conclusion that there is sufficient light, or no noticeable or substantial reduction in light, or in some cases both.

Taking the principal bedroom in flat 705 as another example, which as shown above is deficient on the results of a Waldram, MDF and MDI analysis, Mr Ingram’s report says, in relation to MDF, that:

“… the remaining light that will be enjoyed, is similar at this level (0.56%) as well as the recommended level (0.7%), despite falling marginally short of the guidance. I therefore consider it sufficient against this room’s use and location.”

The false colour images are said to “remain similar”. The room use (as a bedroom) is, however, taken into account in the target proportion (0.7%).

For MDI, Mr Ingram’s results at that stage showed a narrow “pass”, and he says that:

“… the numerical results indicate that the remaining light will be sufficient against this room use and location. The retained MDI value meets the 100 lux recommended value for bedrooms retaining 107 lux demonstrating this is the case”

despite a reduction from 141 lux in the Before assessment. So, where the numerical results support the Defendant’s case, Mr Ingram is content to take them as proving sufficiency, without (it appears from the words of the report) further analysis of the false colour images.

The BRE Guidelines are referred to and exactly the same statement as in [198] above is then made. The conclusion on the Waldram method, suggesting that the remaining light is insufficient, is dismissed on the basis that “I am already clear that this is an incorrect conclusion”. A conclusion for this room, which on the 2025 analysis also fails to meet the MDI standard, is expressed as:

“I am clear that this room will not only retain sufficient daylight but also there will be no noticeable reduction to it.”

Mr Calland criticised Mr Ingram’s approach to assessing insufficiency of light, for the following reasons:

I find most of these criticisms to be justified, either wholly or to some extent. I agree that Mr Ingram’s analysis of the various results leaves a lot unexamined. There is no attempt to analyse the results on which Mr Ingram chooses to rely, so, for example, the false colour images are not further interrogated to analyse how much of each room falls into each colour band or what the proportionate changes are, Before and After. Where different methods of assessment produce the same result, that is not acknowledged; where they produce apparently different results, there is no attempt to explain why they do so, or reconcile them, nor does Mr Ingram take into account the Waldram results or attempt to analyse them.

Mr Ingram said in cross-examination that “you cannot rely on the Waldram basis” and “I don’t accept Waldram is telling the truth”. So he has rejected the Waldram method (on the basis of its methodological shortcomings) and considered only the results produced by the different BRE and Radiance methods. However, the Radiance method and some of the BRE tests do not support his conclusions either, when fairly analysed. The most that can be said is that one or more (but not all) of the BRE tests is passed, sometimes only because there is a reduction of less than 20% in the result. That reduction of 20% is then made to do double work, in explaining why a substandard MDI or MDF result does not demonstrate insufficiency or a substantial impact.

So, as one example, for the bedroom of flat 705 the narrow failure on MDI was said not to be noticeable and a reduction of 14.1 lux (a reduction from 0.6% to 0.5% MDF, where the minimum standard is 0.7%) was “not perceptible” in view of what the false colour images showed, where the Before and After images were “almost identical”. In any event, the loss was not important because the room is a bedroom and any reading in bed would be done with the aid of artificial light.

The false colour images on which Mr Ingram ultimately relied for his judgements about insufficiency and noticeability are produced by the computer programme in standard format, for each MDI and MDF assessment. For MDF, the bands range from 0.0 to 0.5% (blue) to 5.0% (a rich yellow colour), with bands increasing by 0.5% in between (colours ranging from indigo to a slightly lighter shade of yellow). For MDI, the same coloured bands are used but this time on a scale in which each band increases by 50 lux. For both sets of images, the most important bands are 0.5-1.0% (50 lux to 100 lux), 1.0-1.5% (100 lux to 150 lux), and 1.5% to 2.0% (150 lux to 200 lux), which are coloured indigo, magenta and burgundy. These 3 colours and the scarlet colour of the next band above them appear as quite similar shades on the false colour images. Given that it may be material to know which parts of a bedroom are below and which exceed 0.7%, which parts of a living room exceed and which are below 1.1% and which parts of a kitchen exceed and which are below 1.4%, the scale is obviously unhelpful.

Mr Ingram’s view is that to a trained eye the distinctions are clear. He did not explain how he could distinguish on an MDF false colour image between areas of the room that fell below or above the specified minimum standard for the room, but appeared to me to rely on something of a more impressionistic, global assessment.

Mr Ingram’s evidence was, in essence, that by considering the false colour representation of the MDI or MDF results, he (with a trained eye) could understand where within the room the various levels of light fell, in the Before and After analysis, and so was able to discern whether the light in the room was sufficient, in the After analysis, and whether the difference between the Before and After representations would be noticeable, or not.

In the case of the bedroom to flat 605, the difference as shown on the false colour images is just about discernible to an inexpert eye – no doubt as a consequence of the result clearly moving from a “pass” to a “fail” on both MDI and MDF. The principal area of difference is a strip in passing from the window to the head of the bed, where what was burgundy or borderline magenta becomes magenta and indigo. So, in relation to the bedroom, Mr Ingram was able to identify that the areas of loss of light were concentrated over the obvious position for the bed, which meant that loss would not be substantial, as that light could not be used for reading there. On the equivalent images for the LKD, the difference is less easy to perceive, and may be more subtle, but an area of the kitchen where the island unit is located is one noticeable change.

For flat 705, the colour change again appears quite subtle, but the main area of change appears to be the area over the top half of the bed, against the side wall of the bedroom, in the most obvious position for a large bed.

A single colour change on the false colour images can represent a change of up to 1.0% or 100 lux (from the bottom of one band to the top of the next), however, so a broader appreciation of the changing areas of colour is needed to understand the extent and implications of the change, described at one point as a “ripple effect”. A comparison with the Waldram diagrams for the same scenario may assist in identifying areas where the change is most noticeable.

Ultimately, Mr Ingram’s view was that the false colour images reveal not much of a change and that they do not indicate an insufficiency of light overall, but if they do, the change would not be noticeable, given the areas in which it principally occurs.

Mr Absolon said that the false colour images could not be read by a non-expert, and that even for an expert, they were difficult to read because of the scale at which they were produced and the way in which different bands of illumination were similar colours and merged into each other, without clear boundaries. In his own report, he produced a different version of readings, on a different scale with strikingly different colours for adjoining bands of illuminance, for the purpose of demonstrating how false colour images could be made more readable. I agree that his version of the images produces a much clearer representation of the effect of the change. He accepted, however, that an expert could interpret the standard images to inform an understanding of how the light changes within a room.

I am not persuaded by Mr Ingram that the false colour images demonstrate that, despite the results produced by the MDI and MDF assessments (and the Waldram results), the light in the rooms in question is sufficient or that the change would not be noticeable. There was really nothing more to go on than Mr Ingram’s assertion that that is what he considered that the false colour images revealed. There was no explanation of why it is that, despite the results from the highly sophisticated methods that Mr Ingram preferred to rely on, there was in fact no insufficiency of light. The Waldram results and the Radiance results, properly interpreted, tell the same story, though some of the Radiance results are more marginal. I was not persuaded that, on the basis of Mr Ingram’s subjective interpretation of the false colour images, I should reject those results and find that the light remains sufficient.

As to noticeability of the reduction in light, Mr Ingram relies on the same material for saying that the change from cut back Arbor to Arbor as built would be imperceptible, namely the false colour images. The Waldram results (which he rejects) show a very substantial reduction in all cases, and the MDI and MDF results, properly analysed, broadly accord with them. The results show that, whichever method is used, the light in the room either becomes substandard or, in the case of the MDF results, being already substandard becomes materially worse. They give no obvious support for the proposition that the reduction would not be noticeable.

As for the inconsequentiality of the location of the “missing” light, namely over the bed, I do not accept Mr Ingram’s opinion that losses do not matter because bedrooms are for sleeping in and, if one were to wish to read in bed, this would have to be done with the use of artificial light in any event. In the bedroom in flat 705, the main area of “missing” light is the middle and side of the room. As arranged by Mr Cooper, this is over the top half of the bed, but it need not be so. A reasonable use of the space in the room would be to have a bed head where the built in wardrobe is and a desk in or immediately next to the area of “missing” light, with a standalone wardrobe on the opposite side wall. I accept Mr Absolon’s opinion that in this type of flat in London, one should bear in mind that bedrooms may well be used as live/work units by students or young professionals sharing the flat. Even if Mr Cooper’s layout is kept, a person lying on the bed during the day would be able to benefit from the natural light, for reading or otherwise.

In the bedroom in flat 605, the missing light falls over the middle part of the bed, not at the very top, and a smaller area by the doorway into the corridor. Having the bed in its current location is the only reasonable way to make use of a bedroom with an ensuite bathroom.

In both cases, it is a central area of the room where the “good” light is principally lost. It should also be borne in mind that the impact of the insufficiency of light overall in the room will be felt in those areas immediately adjoining the contour line, as the degree of light is a gradient, and those areas closer to the contour line will be relatively less well lit, and on the verge of being insufficient, whereas they were previously well lit.

Mr Absolon’s opinion was that where the proportion of the room that is “well lit” (i.e. on the “window side” of the 0.2% sky factor line) falls below 50%, that denotes a substantially adverse effect on the use and enjoyment of the room, for that is the very thing that the Waldram method attempts to assess. If there is insufficient light for the comfortable enjoyment of premises, that will be a noticeable deficiency, and it is bound to have a substantially adverse effect on the ordinary use and enjoyment of them. He accepted that if premises already have insufficient light, it is then appropriate to ask whether a worsening of the light would be noticeable, and that a 2% margin for imperceptibility was generally allowed, in such a case.

Mr Ingram accepted that although the human eye is very good at adjusting to different levels of light, insufficient light is the point where the eye cannot properly adjust. Once past that point, the light is insufficient, with the result that the impact on use of the room is substantial.

In my judgment, insufficiency of light on the Waldram method of analysis denotes the level at which ordinary use and enjoyment of the room is adversely affected to a substantial extent, subject only to whether the shape of the room or other such factors have produced a distorted result. At a level just above 50%, use and enjoyment may be affected, in that the light is relatively poor, or barely sufficient, but if light is obstructed to that extent only, it does not have a substantial impact. Nor is it deemed insufficient, on the Waldram method of analysis. There is, however, no further margin below 50% within which the effect of the change from sufficient to insufficient is insubstantial, assuming that the Waldram analysis is correctly calibrated. Indeed, one of the criticisms of the Waldram method is that 1 lumen per square foot is unrealistically low, as a measure of the light required for ordinary use of a room.

While it may be true that a change in the degree of diffuse illuminance represented by a reduction from 51.1% to 49.9% on the Waldram method, if it could be experienced in reality, would not be noticeable as a difference, nevertheless, whether such a change were perceptible or not, a proportion of 49.9% is insufficient and, at that level, has a substantially adverse effect on use and enjoyment, whether the occupier is conscious of the change or not. What the occupier will be conscious of, at that level, is that the light is insufficient for comfortable use.

In short, in my judgment, the Waldram method does not require a separate exercise of asking whether the effect of the obstruction is perceptible as a change if the result shows that the light in the room is insufficient. Substantial interference with ordinary use and enjoyment is built into the measurement, if the obstruction causes the level to fall below 50%. I accept, however, that if the Waldram method is adjudged unreliable, the conclusion may not follow, particularly in marginal cases, but that is a different question (see below).

If the light is already at a level where it is insufficient, and the occupier already grumbles because they cannot comfortably make ordinary use of the room, an obstruction that further reduces the level of light to an imperceptible degree may not have any effect at all, let alone a substantial effect on use and enjoyment. A more significant reduction will have an effect because the light will be not just insufficient but perceptibly poorer than that.

Where the claimant's interest in the performance of a contract is purely economic, and he cannot establish that any economic loss has resulted from its breach, the normal inference is that he has not suffered any loss. In that event, he cannot be awarded more than nominal damages.

Negotiating damages can be awarded for breach of contract where the loss suffered by the claimant is appropriately measured by reference to the economic value of the right which has been breached, considered as an asset. That may be the position where the breach of contract results in the loss of a valuable asset created or protected by the right which was infringed. The rationale is that the claimant has in substance been deprived of a valuable asset, and his loss can therefore be measured by determining the economic value of the right in question, considered as an asset. The defendant has taken something for nothing, for which the claimant was entitled to require payment….”