Ultraframe (UK) Ltd. v Eurocell Building Plastics Ltd.& Anor

The claimants, Ultraframe, and Eurocell (as I shall collectively call the two defendants) make and sell kits of parts for making low pitch conservatory lean to roof assemblies. Speaking generally these assemblies are made from long (up to 4m x .5m) hollow UPVC panels joined together and provided with sufficient strength. Ultraframe sued Eurocell in respect of its product called Pinnacle 500, a competitive product to Ultraframe’s Ultralite 500. The claim was for infringement of patent No. 2,300,012 and of unregistered design right (“UDR”) in the panels, a complete assembly, and in some components for the product (top and end caps and U shaped channels) of the Ultralite 500. Eurocell counterclaimed for revocation of the patent.

By his main judgment, [2004] 1785 EWHC (Ch), [2005] RPC 111 Lewison J held that:

the patent was not infringed;

the patent was valid;

there was no fresh UDR arising from minor changes made to the design of the Ultralite 500 in 1995;

there was no infringement of design right in the components;

but there was infringement by the Pinnacle 500 panels themselves and by the whole assembled Pinnacle 500 product.

By a supplementary judgment Lewison J held that it was legally possible for a defendant to undertake, pursuant to s.239 of the Copyright Designs and Patents Act 1988 (“CPDA”), to take a licence under s.237 even though at the time of the undertaking rights in the design had expired. The effect of this is to limit the amount of damages which can be claimed for infringement of UDR to twice the royalty which would be fixed by the Comptroller.

Ultraframe appeals the finding of non-infringement of the patent and the s.239 decision. It does not appeal the finding of non-infringement of UDR in the components nor the finding that no fresh UDRs were created in 1995. Eurocell appeals the findings of infringement of UDR (i.e. in panels and whole assemblies). It also appeals the finding of validity of the patent but only if the court concludes that the patent covers the Pinnacle 500.

The Judge approached the problem via the so-called “Protocol” questions. After he did so the principles as to the determination of the extent of a patent monopoly have been clarified by the House of Lords in Kirin Amgen v Hoechst Marion Rousel [2004] UKHL 46, [2005] RPC 9. The result of that case is that the key principle is simply one of construction of the claim, read in the context of the description and the drawings:

Although the Protocol questions can be a guide, their application often produces unnecessary difficulties. They require, for instance, the court to consider a “variant” – which begs the question “from what?” I therefore propose to go straight to the compulsory question.

Before the court gets to the examination room it has to do some swotting: to get into its mind the relevant knowledge of the skilled man. For how a document will be understood depends on the reader. The reader of the compulsory question is a notional figure, the skilled man, whose attributes I summarised in Technip France’s Patent [2004] EWCA Civ 381 [2004] RPC 46 at paras [6-8].

Lewison J summarised much of this in paragraphs [4] to [17] of his judgment to which reference may be made for detail. He also in paragraph [78] said this, which was also uncontroversial:

If you were fixing roofing panels for a lean-to conservatory you would fix them one at a time;

While you were fixing them you would be working above your head;

To fix them at all (if you were working on your own) you would need to support one end of the panel at the wall-plate (against the wall of the main building) and the other end on the front frame of the conservatory;

Each panel would invariably have some flexibility, as well as uneven edges produced either by the extrusion process, or their subsequent treatment on site or in transport. The extruded plastic panels would often be "laterally bowed" (caused by thermal shrinkage in extrusion) i.e. would be slightly banana shaped along their length;

When the first panel was fixed in place, it would be very difficult to ‘line up’ the next panel all the way along its length especially if you had to engage the second panel at an angle to the first;

Because of these characteristics of extruded plastic panels, it was difficult for the manufacturer to achieve exactness, and tolerances would be expected.

It is necessary to elaborate a little more on how a particularly well-known prior art system worked. It was called the Everlite 250. This can be done by reference to the drawings of Patent No 2,243,170 for it was common ground that fig. 3 of this shows it:

This shows two panels assembled together. The bottom part 120 (coloured brown) of one panel is hooked over part 122 of the other. At the top 132 is hooked over the top of the vertical wall 104. When the roof is being installed it is necessary to start from the left. The first panel (about 4m long and 25cm wide) is laid with one end on the outer wall of the conservatory and the other on the wall plate fixed to the side wall of the house. The next panel has to be hooked over the first. This prevents horizontal movement before the stiffener is inserted (blue, 150). To hook it over is fiddly – partly because of the imperfections such as the banana shape noted by Lewison J and partly because in any event the right hand panel has to be lifted above, and manoeuvred by angling, over the top of the “hooks.” This of course would be impossible or very difficult if there was an overhanging roof (the underside of which is called a soffit) as there would be for some bungalows.

After the panels are hooked together there is a duct between them. The aluminium stiffening member 150 is pushed into the duct. This provides both strength and stops vertical movement between the panels. So in the final structure the panels are held together in two ways: horizontally by being hooked together and vertically by the combination of the formations on the two panels and the stiffening member.

I have sought to describe this in words, though we had the advantage of samples of the Everlite from which I can well appreciate the fiddly nature of the job of hooking long (up to 4m.) panels together overhead. We were also provided with samples of other prior art products which had the same problem. The skilled man would, of course, have been familiar with the problem from his experience.

It is with that background that the skilled man would come to read the patent. It is entitled “structures.” So he will not be surprised to find, in due course, that the claims are directed at structures, not to methods. The first paragraph is a recognition generally of prior art of the kind I have already discussed:

There follows an acknowledgement of four prior patent specifications, namely UK 1528874 (“Sokoler ‘76”), UK 1,511,189 (“Sokaler ’78), EP 0070930A (“Sokoler 83”), and UK 2,147,334B (“Bastionsen”). The precise detail of each of these does not matter for present purposes. It suffices to note that in all of them the panels are provided with means so that they are connected together - “interconnected” – to use the word used in the opening paragraph. There is no specific acknowledgement of the Everlite 250 Patent I have just mentioned, but the paragraph of course would be seen as applying to that too.

Next the patent points out a problem with these earlier proposals:

There follows a paragraph which neither side could explain, but upon whose unintelligibility nothing turns so I do not repeat it. The patentee then says “An object of this invention is to provide an improved building structure” and comes to his invention. He sets it out in a consistory clause which is the same as claim 1:

There follow some explanatory paragraphs:

Omitting some matter immaterial to the present dispute, the patentee next comes to describe what is shown in the drawings “by way of example only.” Figure 2 shows two panels joined together and is sufficient for present purposes:

The lower parts of the two panels have portions 24 and 26 which touch each other via what was called in argument a “C” shape. The upper parts of the panels do not touch each other – the stiffener is between them. The whole thing is held together by the stiffening member 44 (coloured blue). The top is covered with a cap.

The language used to describe the connection at the lower end reads:

And that for the connection at the upper end:

The manner in which the lower parts are all held together is described thus:

And the holding together of the upper parts is described this way:

Finally the patentee describes how the parts are put together:

To explain the context of the dispute I leave the specification for a moment to describe the defendants’ Pinnacle 500. It looks like this:

If one now looks at the drawing of the patent in suit there is a difference – the right hand plate has a formation which is fitted into the C piece of the left hand plate. Vertical movement between the plates even without the presence of the stiffening member is, in principle, not possible, though obviously without the stiffener there would be no effective interlocking – the panels would come apart readily.

Whether or not claim 1 covers the Pinnacle product depends on the meaning (ascertained applying the principles I have mentioned above) of the last words of the claim:

The patentees say these require no more than that in the completed structure there should be parts on the lower sides of the panels (“lower coupling members”) which are formed (“formations”) so as to “interengage” (i.e. held abutting each other) and so that the whole structure is held together by the stiffening member. This is unlike the prior art where the parts are linked together before the stiffening member is inserted. So far as the claimed invention is concerned the stiffening member does “double duty” – essentially both locking together the parts and providing rigidity.

The defendants say the claim is narrower: that “interengage” requires more than that the two panels abut each other – there must be some sort of interlocking or partial restraint of movement between the panels. Lewison J accepted this contention. He said [94]:

His language is of course in terms of the third Protocol question. Following Kirin-Amgen one does not really ask that question in that way. One simply tries to read the language of the claim as it would be understood by the skilled man.

The skilled man would approach the patent first by reading the description and the drawings. He would particularly envisage the panels as described actually being used. It is important here really to try to get into the mind of the skilled man. He would have a “feel” for what the panels would look like, how they would be put together in practice. To him the description of how the structure of the invention is put together would be a revelation – just put the panels next to each other and fit in the stiffener to hold them together. He would see that the C-shape of the specific embodiment was of no or little significance technically – it is at most a vestigial and unnecessary remnant of the essential interlocking of the prior art. Unlike anything in the prior art the panels are not held together horizontally (“interconnected” to use the patentee’s word in the opening paragraph).

All you need to get the stiffener in is that the lower coupling members abut each other and are aligned vertically. The C shape might help a bit with the latter, but is obviously not essential. This the Judge acknowledged at [82]:

With that technical understanding he would come to the claim, knowing that its purpose is to delimit the invention. What would he make of the made-up word interengage in context? He would know that the word is not a term of art – a word having a precise technical meaning. It is actually not a dictionary word at all – the patentee has coined it for the purposes of conveying a meaning in context. It follows that going to the dictionary (at the best of times dangerous because one is going out of context) is no use. One can say this: that the word “engaged” out of context, can mean merely “abut” or mean more, somehow joined or linked to. The full meaning is not that precise and must depend on context. It is the context of the technical teaching of the patent which matters here.

Fairly clearly, the skilled man would say interengaged is not meant to convey the kind of connection known in the prior art. Something less is obviously meant by way of distinction from the prior art. Would he nonetheless read the word as requiring some sort of linking – a linking less than a proper “interconnection”. Such a linking would serve no significant technical purpose (and no purpose is mentioned). He would recognise that if it does have this narrower meaning then the patentee has put in a technically pointless limitation.

I think the skilled man would be unlikely to approach the words wherein lower coupling members comprise formations that interengage with formations of neighbouring elements as aimed at achieving either something covered by the prior art or as requiring a purposeless minor restraint against purely vertical relative movement.

But he would recognise that they are words of limitation and must have some point and effect (see Step v Empson [1993] RPC at 522). The Judge thought they would have no meaning if they did not require some sort of restraint or coupling.

Mr Thorley pressed that point on us at the heart of his submissions. I do not accept it because I think the words do have content without conveying the suggested limitation. Without the words the claim would read the elements further comprising integral coupling members on opposite sides … held together by a stiffening member between the elements. The omitted words clearly do import an extra limitation – they require that it is formations on the lower coupling members which are to be interengaged. And it is these lower coupling members which are held together by the stiffening member. If you omit the words then there is no requirement of coupling by lower members at all – and the notion that it is those lower coupling members which are held together in the final structure (“interengaged”) is missing.

I think this is confirmed by the passage immediately following the statement of invention. It says the stiffening beam has “lower formations” for “holding together lower coupling members”. There is nothing in that passage about any other means for “holding together.”

Mr Thorley had a variant of his meaningless point. He said that if interengaged covered merely abutting and held together, then the claim was repetitious. For the claim requires that the lower coupling members are held together by the stiffening member anyway. So what, he asks, does interengage add? I agree it adds little – but it adds something. For the claim specifically directs attention to formations on the coupling members. It is specifically these which are to be interengaged. And in any event, even if there is some repetition, it is explicable on the basis that this part of the claim introduces the requirement of such formations and the repetition is merely emphasising the fact that it is these which are held together by the stiffener.

To my mind Mr Thorley’s submissions bore some resemblance to the “meticulous verbal analysis” which does not form part of the approach to patent claim construction (see [46(k)] of Technip France’s Patent). It is a strong thing to say that a claim has a technically purposeless limitation – though of course if it does the limitation must be given effect. There is no sufficiently compelling reason to do so here.

I reach this conclusion without support from the patentees’ further argument based on claim 3. The argument is this: that the width of claim 1 must be wider than claim 3 and that it was only claim 3 which contained a limitation requiring some prior restraint. It is an example of the argument epitomised by the late Anthony Walton QC: “Claim 1 ‘A car’; Claim 2 ‘A car wherein the wheels are round’” – forcing you to the conclusion that claim 1 covers cars with non-round wheels. That sort of argument, although it has its uses, can descend into overmeticulous verbal analysis.

Save in one minor respect Mr Thorley concentrated his attack to reliance on fig. 2 of Patent No 2,243,170:

This shows the left hand panel hooked over an upstand on the right hand panel. Unlike the commercial embodiment, shown in fig. 3, there is no corresponding hooking of upper elements. Instead there is a top cap 50 which holds the top end of the assembly together. The drawing shows the beginning of the top of the panel itself (18). It is not flat but arcuate. The text of the patent says about this:

The disclosure is said to novelty-destroy claim 1, or render it obvious if the only difference between claim 1 and the disclosure is that the claim is limited to flat top walls whereas the disclosure is limited to arcuate top walls. In connection with the alternative obviousness plea I should mention that we gave permission to appeal on this ground during the hearing. It was not originally the subject of permission or an appeal. Our reason for giving permission is that, although the application was made at the very last minute, it was really a point of argument and Mr Baldwin QC for Ultraframe could not suggest that his clients had been prejudiced in any way by the lateness of the application.

It is convenient to deal with the “not flat” point first. I think that the disclosure saying that an arcuate top is preferable amounts to a disclosure of a flat top too – the preference is clearly also a disclosure of the alternative. And even if that be wrong, a flat top is a technically obvious alternative, as indeed was acknowledged by Ultraframe’s expert witness, Mr Savage.

So the real question is whether fig 2 of the patent falls within the closing words of claim 1. Does it disclose “elements further comprising integral coupling members on opposite sides, wherein lower coupling members comprise formations that interengage with formations of neighbouring elements and are held together by a stiffening member between the elements?”

The answer is no. What holds the lower coupling members together is the hook means, not the stiffener. This is indeed the same difference as is to be found in the prior art specifically acknowledged in the patent so it is improbable that the claim would be intended to cover it (see Beloit v. Valmet [1995] R.P.C. 705 at 720).

So the patent is valid over the Ultralite patent. Mr Thorley in reply suggested that there might be anticipation by Sokoler 83. But the argument is defeated by the same point – the panels are interlocked and held together by end hooks prior to insertion of the stiffener.

Accordingly I would hold that the patent is both valid and infringed.

The issues here are:

Design right is a property right which subsists in accordance with this part in an original design.

In this Part ‘design’ means the design of any aspect of the shape or configuration (whether internal or external) of the whole of part of an article.

Design right does not subsist in –

A method of principle of construction.

features of shape or configuration of an article which –

enable the article to be connected to, or placed in, around or against, another article so that either article may perform its function, or

are dependent upon the appearance of another article of which the article is intended by the designer to form an integral part, or

surface decoration.

A design is not ‘original’ for the purposes of this Part if it is commonplace in the design field in question at the time of its creation.”

The owner of design right in a design has the exclusive right to reproduce the design for commercial purposes –

by making article to that design, or

by making a design document recording the design for the purpose of enabling such articles to be made.

Reproduction of a design by making articles to the design means copying the design so as to produce articles exactly or substantially to that design, and references in this part to making articles to a design shall be construed accordingly.”

Mr Thorley contended that the Judge erred in principle when he accepted the submission that the design field in question (s.213(4)) was limited to conservatory roofs. If one went wider, so as to include all kinds of roofs, doors and that sort of thing, one would find that the design was indeed commonplace.

The Judge said [124]:

The day before Lewison J gave judgment, this Court decided Lambretta v Teddy Smith [2004] EWCA Civ 886 [2005] RPC. Lewison J did not know about the case when he gave judgment. It is clear from Lambretta that he took too narrow a view of the meaning of “design field in question”, see Lambretta at [43] – [47], particularly the sentence of my judgment reading:

The judge therefore applied the wrong test, as indeed Mr Baldwin conceded. I would add this: that if the Judge’s test were right, a designer would be able to obtain UDR in designs with which other similar designers were wholly familiar, just because the “field” was narrowly drawn. That would be to impose too much of a fetter on freedom to use known designs. One can test the point by a notional example. Suppose conservatory designers were completely familiar with a well-known design of window panel. Why should the law give a particular designer UDR protection for choosing to use in a conservatory a design known to all conservatory designers?

I should add this: the Judge was impressed by the fact that Mr Savage, an expert witness, asserted without challenge that the “design field in question” was limited to conservatory roofs. This was not really a question for the expert witness. What matters is the kind of material which would be well-known to designers of articles of the type in question. The expert’s function is to provide information as to that. Here there was considerable evidence that designers of conservatory roofs had a wider perspective than just such roofs. Mr Savage himself had much wider experience: “I have spent my entire working life dealing with windows, doors and conservatories”. He regularly attended exhibitions here and in Europe and read trade magazines which included windows, doors, conservatories and the sort of materials used to make them including plastic roofing materials.

So was the design of the panels commonplace in this wider field? This is question upon which I have to answer myself, given that the Judge’s opinion was based on too narrow a view of “design field in question.” Mr Thorley took us at a canter through some of the materials relied upon. At first I was impressed with this, but Mr Baldwin made us consider it in more detail. As a result I am satisfied that the design was not commonplace, even in that wider field.

What was shown to be well-known and hence commonplace was two or three walled hollow plastic sheeting material which comes in large sheets intended to be cut down for appropriate roofing uses. The ducts were, in some cases, square in cross-section and the thickness was up to 16mm. The Judge excluded this material from his consideration of what was commonplace because it was not part of the conservatory field. But even taking it into account I do not think that the design of the Ultralite panels is rendered commonplace. For the panels are very different: 60mm thick 500mm wide and 4m long, provided with rectangular ducts and with the coupling means at each edge and an overhanging drip.

Closer in design were two products shown in the catalogues of two German extruding companies, Prokulit and Rodeca. They are indeed 60mm thick 500mm wide, triple walled with rectangular ducts. The Prokulit product is provided with a tongue and groove means of joining.

However it is not necessary to decide whether these products affect the subsistence of design right in the Ultralite product, for in our judgment they were not proved to be commonplace. Whether or not the products had significant sales is not known. Some last minute hearsay evidence was far from showing that they had widespread sales in this country – indeed it is not clear they were sold at all. True it is they were in the two extruders’ catalogues, and that there was apparently no UK extruder with a capacity to make extrusions of this shape. And it may well be that anyone interested in a panel of that size and shape would have to go abroad to find a maker. But that is miles away from showing that panels of this size and shape were commonplace.

Perhaps the most telling thing about these products is the fact that Mr Savage, notwithstanding his widespread experience, did not know of them. Nor, fairly obviously one can infer (for they were not called) did the defendants’ experts – reliance on the panels was added by late amendments shortly before trial. That which is commonplace in a design field will be ready to hand, not matter that has to be hunted for and found at the last minute. After all, one is trying to prove a prior design is commonplace, not merely (as for instance in a patent case) that it was made available to the public by use.

As for infringement, the Judge said this [137]:

Moreover the Judge’s conclusion on infringement is the sort of evaluation which it is difficult to disturb on appeal, see Designers Guild v Russell Williams [2001] FSR 11. Here I cannot see the beginning of a reason for doing so. I would uphold his finding that the Pinnacle panel infringes the UDR in the Ultraframe panel.

Mr Thorley’s point here was that the assembly of panel, top and end caps could not be the subject of a separate UDR. This was put on the basis that UDR did not subsist in the individual components because they were commonplace. For present purposes I assume that to be so, though I have held the contrary in relation to the panels and, although Lewison J found that the top and end caps did not infringe, it was not on the basis that there was no UDR in them by reason of their being commonplace.

Lewison J’s reasoning was simply this: that design right can subsist in an assembly of individually commonplace parts: that “this is a legal form of ‘gestalt’ in which the whole is more than the sum of its individual parts”.

Mr Thorley did not attack this as a general proposition. In argument he accepted the example of an original model made from Lego bricks as a perfectly acceptable subject of design right. But he submitted that things were different here because there was no individual skill and labour involved in the design of the overall assembly. The only skill and labour involved was in the design of the parts, which, once designed, could only be put together in one way: there was no skill and labour involved in the assembly, unlike the case of the Lego brick model. Putting the assembly together was a purely non-creative mechanical task.

The argument fails for the simple reason that it has no basis in fact. The design process involved the conception of the whole as well as the parts from which it is to be assembled. The whole formed part of the skill and labour. Indeed it is not possible to imagine designing the parts as a separate operation from designing the assembly. Moreover at [125] Lewison J accepted the evidence of Mr Savage:

Accordingly I think Lewison J rightly concluded that there is UDR in the roof assembly and that it was infringed.

I should add that there was some debate before us on the “must-fit” exception to UDR contained in s.213(3)(b)(i). We were referred to the conflicting decisions of Laddie J in Electronic Techniques v Critchley Components [1997] FSR 401 and David Young QC in Baby Dan v Brevi [1999] FSR 377. These are about whether UDR can subsist in an assembly solely by virtue of the design of the interconnections between the parts. So they were not relevant to this case where the assembly as a whole is the subject of UDR independently of the design of the interconnections between the parts. Lewison J followed the later of the two decisions and discounted the U-shape of the interconnection here. He did so without deciding which of the two decisions was right, in accordance with the settled practice where there are two conflicting decisions.

I considered whether I ought to try to resolve the problem. But in the end I have concluded that no real useful function would be achieved. This is for three reasons. First this is not a case where there is no UDR in the assembly as a whole apart from the manner of the interconnections. So whatever I said would only be obiter. Secondly the problem is likely to be rare – cases where an overall design of an assembly of parts (e.g. a car) is not the subject of UDR (e.g. because commonplace or expired) but the components (e.g. body panels) are (e.g. because redesigned later) are difficult to imagine. Thirdly, if and when the problem does arise, it would be better to decide it on concrete facts.

In the result I would uphold Lewison J’s findings that the panels and assemblies infringe UDR.

In view of my conclusion (with which I understand Mummery LJ agrees) in relation to the patent there will be an award of damages for patent infringement. So this point is probably academic. However I agree with the judgment of Neuberger LJ on the point and would only add this: that it is very difficult to see the logic of the provision. For once an intellectual property right is subject to a licence of right, the normal level of damages for infringement is the appropriate royalty rate, just as it is for a patent whose owner exploits it by licensing. Clearly the provision has not been thought through.

I have read in draft the judgment of Jacob LJ. For the reasons he gives, I agree that the cross-appeal on the design right issue should be dismissed. However, albeit with diffidence, I have come to a different conclusion from him as to the proper construction of the patent in suit. For my part, I would dismiss the appeal on that aspect.

I shall confine myself in this judgment to two aspects of this appeal. The first is to explain why I take a different view from Jacob LJ (and indeed from Mummery LJ) as to the interpretation of the patent. The second is to explain why I consider that the judge was right to conclude that Eurocell was entitled to offer an undertaking under section 239 of the Copyright, Designs and Patent Act 1988 (“CPDA 1988”) notwithstanding the fact that the design right in question had expired.

The proper approach to the construction of patents has been discussed in a number of cases which have been referred to by Jacob LJ in his judgment, and it is unnecessary, indeed inappropriate, for me to refer to them again. However, particularly as I have arrived at a different conclusion from Mummery and Jacob LJJ, it seems to me right to emphasise one or two points of principle before turning to the more specific involved in this case.

First, although one must avoid “detailed semantic analysis” of a patent, as of any other document, when interpreting it, one cannot get away from the fact that the process of construction involves interpreting the words used by or on behalf of the patentee (together with any chart or figure) in the patent itself. Secondly, one must of course interpret those words in a contextual way, and, in relation to a patent, the context includes common general knowledge. Thirdly, there is the factor that one is reading it through the notional eyes of the relevantly skilled person.

Fourthly, one must be careful of being seduced into construing the patent in reference to extraneous circumstances, which cannot fairly be said to be part of the context. In this connection, most patent cases in this jurisdiction (and the present case is no exception) involve the court having to construe the patent and to consider an alleged infringement in the same proceedings. I accept that it may be wrong to divorce the two concepts altogether, but it cannot be right, purely as a matter of principle, that a product or process which, ex hypothesi, will have come into existence after the priority date of the patent, to be used as a means for interpreting the patent. Even less defensible is the notion that the patentee can pray in aid a physical demonstration of what he contends is the product claimed by the patent in order to justify that very construction. This is not to say that a physical demonstration will be unhelpful: on the contrary, in many cases it will be of great assistance.

The reason for emphasising these points is that I am conscious of a strong desire, at least in myself, to construe the patent in the sense contended for by the patentee, and, indeed, adopted by Mummery and Jacob LJJ. The principle reason for this is that it does appear that the patentee, Ultraframe, had developed (or purchased someone else’s development of) a structure which has the effect described by Jacob LJ in his judgment, and which appears to me to have been ingenious and novel, and, indeed, worth copying, as the facts of this case, as found by the judge, demonstrate. Accordingly, if, as I have reluctantly concluded, the patent does not have the meaning for which Ultraframe contend, they have lost a monopoly right which they intended to obtain, which it seems to me that they deserve, and which it could be said that they have lost only on technical grounds.

With those slightly hand-wringing observations, I turn to my reasons for concluding that the patent does not extend to the inventions to which Ultraframe claims it extends. I think it is important to begin by identifying the nature of the invention which, according to Ultraframe’s contention, the patent reveals. In that connection, I cannot do better than refer back to the “revelation” identified by Jacob LJ. One would “just put the panels next to each other and fit in the stiffener to hold them together”. In other words, “unlike anything in the prior art the panels are not held together horizontally…. All you need to get the stiffener in is that the lower coupling members abut each other and are aligned vertically”. Unlike in the prior art, until the stiffening member is introduced, the lower coupling members of the two adjoining panels are not interconnected or interlocked in any way: they merely abut each other. The stiffening member not merely stiffens, but itself interconnects with the two lower coupling members whilst causing them to be (albeit indirectly, through the medium of the stiffening member) interconnected with each other. The crucial point distinguishing this invention from the prior art is that the lower coupling members merely touch each other and are not in any way locked together, whether directly or indirectly, until the introduction of the stiffening member.

In determining whether the patent extends to this invention, or revelation the issue centres on the closing part of claim 1, which is in these terms:

Although one must be careful not to concentrate too much on individual words, or even individual parts, of a claim, it appears to me, as it seems to appear to Jacob LJ and, indeed, to have appeared to Lewison J, that a word of central importance in the present connection is “interengage”.

The fact that “interengage” is not to be found in a dictionary does not appear to me to be particularly significant. Dictionary definitions, being acontextual, are, by their very nature, of questionable value on issues of interpretation of documents: in my opinion, they are as likely to mislead as to help.

Quite apart from this, it seems to me that the prefix “inter” before a noun or verb, which is in some way concerned with relationships, normally means a relationship between two previously identified things, individuals or groups. Thus, one can talk about two physical components interconnecting, one can talk about two groups of people intermarrying, and one can talk about the interplay between two individuals. Accordingly, I would have thought that the natural meaning of “interengage” is “engage with each other”.

Of course, this analysis must be applied with some caution before extending it to the construction of a particular document, such as the patent in suit. As I have mentioned, it can be worse than useless to try and construe a word in a hypothetical or otherwise acontextual way. My concern is simply to explain why I do not think that much can be made of the fact that “interengage” is not to be found in the dictionary. To any ordinary speaker of English, it seems to me that, given that the prefix “inter” is familiar and has a potentially reasonably clear meaning, and the word “engage” is plainly a common word, the conflation of the two should not, at least normally, present any particular difficulties.

There are a number of reasons why I cannot accept that the word “interengage” in claim 1 of the patent in suit merely means “abut”, and excludes any question of interlocking or interconnection. As often happens with questions of construction, the effect of these reasons is cumulative, and the order in which I take them is for the purpose of clarity rather than importance.

First, at least to me, the natural meaning of “engage”, and therefore of “interengage”, when one is discussing two components, carries with it more than mere touching. I appreciate that some dictionaries include a meaning of the word which involves mere touching, but others do not. To my mind, it is not a natural use of the word “engage” to interpret it as meaning no more than “abut”.

Secondly, if the “revelation” of the patent in suit is as described by Jacob LJ (as I have briefly quoted above), then it is somewhat extraordinary that the word “interengage” is used, rather than a simpler and clearer word such as “touch” or “abut”. I accept that to argue that, if a party had intended a particular meaning, he would have expressed himself differently, is often a cheap and worthless point to make in an interpretation dispute, because both parties can make it, normally with equal force. However, in the present case, I think the point has force, because, on the patentee’s argument, the word “interengage” is what carries with it the essential claim to the invention. The notion that a revelation of this patent is that the lower coupling members need only abut and need not be connected does not, to put it at its very lowest, appear very clearly from claim 1. If it is intended to be the essential (or, on the most generous possible interpretation of the invention contended for, an essential) innovative feature one would have expected it to have been flagged up in clear terms.

Thirdly, I consider that Mr. Thorley is right in saying that the patentee’s interpretation gives precious little, if any, meaning to the words “interengage with formations of neighbouring elements”. In that connection I differ slightly in my reading of the claim, principally because of the comma after the words “opposite sides”, from Jacob LJ. It seems to me pretty clear that the closing part of claim 1 refers to “lower coupling members which comprise formations that [a] interengage with formations of neighbouring elements, and [b] are held together by a stiffening member between the elements”. If (a) simply means that they are held together, as the patentee’s argument involves, then it seems to me to add nothing of significance to (b).

If one casts ones eyes outside claim 1 and to the remainder of the patent in suit, it appears to me that there are a number of further reasons for supporting my conclusion. Fourthly, in the next sentence but one after the consistory clause (which, as Jacob LJ has explained, is in precisely the same terms as claim 1) there is this:

It is clear from the drawings accompanying the patent, and it is agreed, that, unlike the lower coupling members, the upper coupling members do not touch, and that they and the top of the stiffening member are so shaped as to enabling the stiffening member, when it is slid in, to interconnect on each of its two sides with one of the upper coupling members. Thus, to use the words of the patent, the stiffening member “engage[s]” with the upper coupling members. If that is what “engage” means in that context, it provides strong support for the notion that “interengage” in the same document has the same effect.

I should add that this is entirely consistent with what one finds towards the end of the description, which says that the stiffening member is “slid into the space between the elements to fix the lower coupling members and engage the upper coupling members”. In other words, the lower coupling members are already “engaged” before the stiffening member is introduced.

Fifthly, the passage I have just quoted throws some further light on the relationship between the stiffening member and the lower coupling members. It suggests that the only function of the stiffening member in relation to the lower coupling members is merely to hold them together, rather than to engage with them, which again suggests that they are already interconnected.

Sixthly, there is the description of the “preferred lower coupling members”. As Jacob LJ has explained, it involves “a first member that is a horizontal channel into which a second member fits” and goes on to describe them as the “said engaged first and second members”. I accept that one has to be careful of giving too much weight to the effect of “preferred” versions in patents, when construing the claims. Nonetheless, it seems to me somewhat strange to conclude that the revelation of the patent is that the two lower coupling members need only abut and do not have to interconnect, when the specific preferred design of those members involves them doing just that, interconnecting.

Seventhly, the passage I have just quoted referring to the preferred design specifically describes the lower coupling members as “engaged”, before being held together by the stiffening member. Given that, in a couple of sentences before, the stiffening member was described as having “formations for engagement with upper coupling members”, thereby meaning interconnection, it seems to me that the preferred version provides a yet further reason for rejecting the patentee’s construction.

Eighthly, there are the figures attached to the patent. Those figures are introduced by the words “This invention will now be further described”, albeit that those words are followed by “by way of example only”. There is no doubt, as Jacob LJ has said, that figure 2 shows, first, the upper coupling members do not even touch each other, but are so designed (as is the stiffening member) as to be interconnected to opposite sides of the stiffening member, or, to use the words of the patent, so as to be engaged by the stiffening member. There is also no doubt that the lower coupling members in figure 2 are not shown merely as touching or abutting, but as having formations which enable them to be interconnected, albeit that they would not thereby be fixed together, at least confidently or safely. One of the lower coupling members has a C-shaped channel to which the L-shaped other lower coupling member fits. On the face of it, the two might easily come apart unless and until the stiffening member is installed, but, given that the panels containing the coupling members would be parts of a roof, it may well be that they would not come apart very easily, even before the insertion of the stiffening member.

Ninthly, such an interpretation appears to me to be consistent with what the skilled person, reading the patent, would understand it to mean in practical terms. The interengaging, of the lower coupling members, while falling short of actual interlocking, would prevent relative movement of the two panels while the stiffening member is being slid in. Thus, as the description records, the lower coupling members are not actually locked to each other until introduction of the stiffening member, but they are engaged with each other, in the normal sense of the word “engaged”.

Finally and going back in the patent, there is a passage which identifies the problem with the prior art, which is in these terms:

It seems to me that this is not the problem which Jacob LJ has, to my mind correctly, identified as being that which would be solved or ameliorated by the invention which, on the patentee’s case, this patent claims. Once again, I do not pretend that that is a conclusive point, but it does appear to me that the fact that particular invention is said to solve a different problem from that identified in the patent is at least a supporting reason for doubting whether the patent really extends to that invention.

Thus, in agreement with the Judge, it seems to me that the reading advanced by Ultraframe, the patentee, is not in accordance with the natural or the contextual meaning of claim 1 of the patent, or the description of the invention in the patent, or the preferred version as identified in the patent, or the figures attached to the patent, and it does not meet the problem with the prior art identified in the patent.

The arguments advanced on behalf of the patentee to the contrary do not, to my mind, really call into question the combined effect of these points. First, there is the contention that it is hard, indeed quite conceivably impossible, to identify, in the eyes of the notional skilled reader what invention the patent in suit is claiming if it is not that now contended for by the patentee. I am unimpressed with that argument, at least in the context of this patent. I accept that if, for instance, one thought that the patent was genuinely ambiguous, and that it would be read by the skilled man as having two possible meanings, one of which was innovative and the other of which was not, then there might be a powerful argument in favour of the former reading (although the result would probably be different if the ambiguity was such that the skilled reader might not appreciate the innovative reading at all). However, in the present case, the essential problem for the patentee is that, on a fair reading, I consider that the patent in suit does not reveal anything new; accordingly, to contend that it should be read as if it did merely involves reverting to the arguments as to why, at least in my view, it cannot be read in that way.

Secondly, there is the point that the patent uses the word “interconnect”, which should therefore be given a different meaning from “interengage”. I accept that when interpreting a document, there may be a mild presumption in favour of not giving different words the same meaning, but I do not regard it as a particularly strong presumption. In the present case, it seems to me far more significant that the parties have used the word “engage” to mean more than just touch: hence “interengaged” is likely to mean more than just touch. Further, if one is contrasting expressions, it is perhaps not illegitimate to refer to the fact that towards the end of the description, reference is made to the elements being “laid side-by-side”. While I do not regard it as much, if anything, of a point on its own, it is fair to say that laying side-by-side is what happens to the “interengage[d]” lower coupling members on the patentee’s case.

Finally, the patentee relies on claim 3. To my mind, it does not assist the patentee’s case. It seems to me that claim 3 makes perfect sense, if one has read claim 1 as requiring a degree of interconnection between the two lower coupling members. All claim 3 does is to identify more precisely the nature of the interengagement, namely “a horizontal channel in one member into which a second member fits”. Claim 1, on the other hand, can apply to any type of interengagement. Indeed, in my judgment, claim 3 accords more happily with that reading, than with the patentee’s reading, of claim 1. If the “revelation” of claim 1 is that one need have no interconnection between the lower coupling members until the introduction of the stiffening member, it is difficult to see why the patentee would want the patent to extend to a claim where there is such interconnection.

For these reasons I think the Judge was right in his conclusion as to the meaning of the patent in suit and it would follow that Ultraframe’s case on infringement should fail.

I now turn to the second issue with which this judgment is concerned.

Following the handing down of his main judgment, Lewison J was offered an undertaking on behalf of Eurocell pursuant to s239 of CPDA 1988, with a view to limiting the damages which Ultraframe could recover for breach of its UDR. Lewison J accepted the undertaking, and in so doing he rejected Ultraframe’s argument that it was not open to Eurocell to invoke s239 because the design right in this case had expired by the time that the undertaking was offered.

Before us, Mr. Baldwin has renewed Ultraframe’s contention that it was not open to Eurocell to offer, and therefore not open to Lewison J to accept, an undertaking under s239. This raises a point of statutory construction which is not easy, and which is of some potential more general significance.

Section 239 provides as follows:

Section 237 referred to in the opening part of s239(1), is, so far as relevant, in these terms:

The machinery for determining the terms of a licence granted pursuant to s237 or s238 is set out in s247 of CPDA 1988, which provides that “a person requiring a licence which is available as a right… may apply to the comptroller to settle the terms of the licence”. Section 247(6) provides:

Mr. Baldwin’s contention on behalf of Ultraframe is that s239 cannot be relied on by an infringer once the design right which he is alleged to infringe has expired, because of the use of the present tense in the opening words of s239(1). Section 239(1), he says, can only apply “in proceedings” in respect of an infringement “of design right… in respect of which a licence is available as a right under section 237 …”, and accordingly, he argues, once the design right has expired by effluxion of time, it cannot be said that a licence “is” available in respect of it.

Although this argument has obvious force on the face of it, I consider that it should be rejected. Section 237 confers the right to obtain a licence to do something which would otherwise infringe the rights of the owner of the design right, whereas s239 represents a more limited exception to his rights: it is only concerned with limiting his remedies in respect of infringement. For that purpose, all that s239 requires is the giving of an undertaking to take a licence. It is not necessary for the terms of such licence to be agreed between the parties or settled under s247. Although an undertaking will frequently lead to an infringer obtaining an actual licence under ss 237 and 247, s239 itself is concerned with a hypothetical licence which has a limiting effect on the remedies which can be obtained against an infringer, including a retrospective effect for the purpose of assessing damages – see the closing words of s239(1)(c).

To construe s239(1) as being available to an infringer only so long as the design right subsists appears to me to lead to strange consequences. Thus, it would be rather unfair on an infringer, who had copied in the honest and reasonable belief that there was no design right, and against whom proceedings were brought only after the design right has expired. Such an infringer would, for quite understandable reasons, not have applied, even on a protective basis, for a licence under s237, because of his honest belief that no design right existed. Yet, on Ultraframe’s argument, he would be precluded from claiming the benefit of s239 simply because infringement proceedings had been brought against him after the expiry of the design right, although he would have been quite free to claim the benefit of s239 had the proceedings had been brought before the expiry of the design right.

Indeed, it would seem somewhat surprising, and indeed arbitrary, that, even where proceedings for infringement were brought before the design right had expired, the infringer could claim the benefit of s239 only if he gave an undertaking before the design right expired. Of course, strict time limits, and draconian consequences of just missing them, are familiar in many areas of law, but there is normally a good reason for such time limits. There does not appear to me to be any good reason for such a strict time limit in s239(1). It is not as if there is any magic in the undertaking being given before the expiry of the design right. Indeed, Mr. Baldwin accepts that, even on his argument, if the undertaking is given very shortly before the design right expires, it would still be effective, even though there would be wholly insufficient time for the terms of any licence to be agreed or determined pursuant to s247.

Further, the structure of s239 suggests that the legislature did not intend there to be a time limit in subsection (1) as to when the undertaking has to be offered. It is in s239(3) that one finds the time limit. Indeed, the wide words of s239(3) permit the undertaking to be “given at any time before final Order”, and their effect would be cut down to a very significant extent by the construction of s239(1) advanced on behalf of Ultraframe. It appears to me unlikely that, having provided in terms that the undertaking could be offered “at any time” up to a certain point in subsection (3), the legislature could really have intended there to be an anterior and somewhat hidden time bar in subsection (1).

Further, as pointed out by Mr. Thorley, it is not as if one has to give a particularly strained meaning to s239(1) in order to give it an effect which is both commercially sensible and consistent with the general purpose of s239, when read as a whole. Although I would accept that, read on their own, the first two lines of s239(1) could well be said to have the meaning for which Mr. Baldwin contends, once one reads them in their context, and particularly bearing in mind the points just made, I consider that they cannot properly bear that meaning. Read in context, it seems to me that the licence which “is available as a right” is a licence in respect of the “infringement of design right in a design” and not in respect of “design right in a design”. That reading appears to me to be not merely permissible, but to tie in much better with the closing words of s239(1)(c). Although it is clear from s247(6) that a licence actually granted under s237 takes effect, at the earliest, from the date on which the application is made, a hypothetical licence, the subject of a s239(1) undertaking, is effectively treated as granted retrospectively to just “before the earliest infringement” the subject of the infringement proceedings. Accordingly, the hypothetical licence contemplated by s239 is closely connected with the first infringement by the person who is contemplated as giving the undertaking under s239(1).

At first sight, this might be said to be a somewhat surprising conclusion, because it means that an infringer could give an undertaking to take a licence after design right had expired, which would appear to be an impossibility, because a licence cannot be retrospective in its effect (save to the extent that s247(6) permits, but that provision would plainly not apply in a case where the undertaking is given at a time when the licence has expired). However, as mentioned, Mr. Baldwin realistically accepts that, even on his construction of the section, an undertaking can be offered under s239 in respect of a design right which has only a very short period, even one day, to run at the time when the undertaking is offered. In such a case, there could be no question of an actual licence being granted, because any application could only be made to the comptroller after the design right has expired.

Further, there is nothing in s239 which requires the undertaking to be performed within any particular period, and although I would accept that an application for a licence could be expected to be made to the comptroller within a reasonable time where the design right still subsisted, one would not usually expect such an application to be made until the infringement proceedings had been resolved, by which time the design right may very well have expired. Accordingly, inability to apply to the comptroller because the design right had expired would apply in many cases of contested infringement, and not just where the design right had expired at the time that the undertaking was offered. In such cases, as in the present type of case, it would be for the court to assess the appropriate royalty or licence fee.

It has been contended that, on this interpretation of s239, any person against whom infringement proceedings have been brought, would invoke s239 virtually as a matter of course, in order to limit the remedies which could be sought against him. That is a perfectly fair point, but it appears to me to be a general point about the breadth of applicability of s239. In particular it does not seem to call into question the conclusion that s239 can be invoked even in a case where the design right has expired. Indeed, the fact that s239 is a provision which virtually every alleged infringer, who had not already protected himself by a s237 application, would wish to invoke, seems to me to underline the point that it would be somewhat bizarre if a whole category of alleged infringers, namely those against whom proceedings for infringement were brought after the design right had expired, were wholly prevented from being able to invoke the section.

As this discussion has shown, s239 is a somewhat odd provision. During argument, the question was raised whether it could be invoked by an alleged infringer who had already sought a licence under s237. In my view, there are no difficulties where a person, who has already made an application under s237 (either before or after infringement proceedings had been brought against him), then seeks to invoke s239. As pointed out, s237 is concerned with an application for a licence, whereas s239 is concerned with an undertaking to take a licence, and there is neither any inconsistency nor any overlap between seeking a licence and promising to take one. The point is a little more difficult in a case (which would be unusual, but not inconceivable) where a licence under s237 had actually been obtained by the infringer but infringement proceedings are on foot in relation to alleged infringements prior to the date the licence takes effect under s249(6). It would be absurd if, in such a case, the alleged infringer could not take advantage of s239. The effect of the construction I prefer is that the alleged infringer could invoke that section, because of the conceptual difference between the actual licence granted under s237 and the undertaking to take a licence under s239.

Accordingly, on this issue, we conclude that Lewison J reached the right conclusion, and that he was therefore entitled to accept the undertaking offered by Eurocell under s239.

I agree with the judgment of Jacob LJ on the questions of infringement and validity of patent and the issues concerning unregistered design right and with that of Neuberger LJ on the s.239 question.