Tate & Lyle Technology Ltd v Roquette Freres

This appeal is against an order of Lewison J by which he declared European Patent (UK) No 0 905 138, held by the Defendant (Roquette), to be invalid and accordingly revoked it. He heard the case from 3 to 5 June 2009 and gave judgment on 16 June 2009; the judgment has the citation [2009] EWHC 1312 (Pat). He refused permission to appeal, but permission to appeal was granted by Jacob LJ on the papers on 5 October 2009. Like the judge, we had the benefit of powerful and helpful advocacy on the part of Mr Purvis Q.C. for Roquette and Mr Birss Q.C. for the respondent, (T&L). In what turned out to be his last case as Counsel, Mr Birss articulated his contentions in the elegant and clear manner that the court has become accustomed to on his part, and which will no doubt characterise his decisions as the judge of the Patents County Court.

Lewison J held the patent to be invalid on the ground that it was anticipated by at least five examples of prior art. In order to get to that stage he had first to decide a disputed question on the construction of the patent, which he did in favour of T&L, though he also held that even on Roquette’s construction the patent was anticipated by two items of prior art. T&L had also alleged that it was invalid for obviousness, but the judge said that he would have rejected that argument. The judge also said that the patent amounted to a discovery, not an invention.

Roquette contends that the judge was wrong on construction, and also on anticipation (whether or not he was wrong on construction), and as to discovery. It accepts that if he was right on construction, the appeal fails. In case the appeal were to succeed on any of those points, T&L put in a Respondent’s Notice contending that the judge was wrong to reject its case of obviousness. We had a day and a half in which to hear the appeal, but this did not allow us to embark on the issues raised by the Respondent’s Notice. Accordingly we reserved judgment on the issues on the Appellant’s Notice, on the basis that if our decision were such that the Respondent’s Notice had to be argued, that would happen on a later occasion.

The patent relates to maltitol, a sugar substitute, and in particular to its crystallisation. We were given an illustrative chart (derived from the expert evidence in the case) showing how a sugar is produced from starch by a succession of processes: liquefaction (to produce long chain glucose polymers), then saccharification (to produce short chain glucose polymers) and then hydrogenation (to produce short chain glucose sugar alcohols), before crystallisation.

In paragraphs 4 to 7 of his judgment, the judge described the basic background in a succinct and clear way which I gratefully adopt:

“4.

Sugars are saccharides. Saccharides come in many different forms. Some are monosaccharides, some disaccharides, others trisaccharides and so on. The prefix denotes the degree of polymerisation (i.e. the number of small molecules bonded together) and is abbreviated to DP in some of the prior art. Thus a trisaccharide can be abbreviated to DP3. Saccharides can also be divided into oligosaccharides and polysaccharides. The former have more than one identical molecule bonded together but not very many. If they have many they are polysaccharides.

5.

The process of making maltitol crystals begins with a starch (typically from corn, potatoes or wheat). The starch is first liquefied by the addition of enzymes or acids. Once liquefied, any enzyme is deactivated and saccharification can take place. Saccharification is also carried out by means of enzymes which break down the long polysaccharide chains into shorter ones. Specific enzymes are added to hydrolyse the polysaccharides so as to yield the required type of sugar. On the way to making maltitol, it is necessary to yield maltose, so the additive will be a maltogenic enzyme. Maltose itself consists of two units of glucose linked together and is thus a disaccharide. But the maltogenic enzyme will also produce maltotriose, which consists of three units of glucose linked together and is thus a trisaccharide. There are other by-products of enzymatic maltose production (e.g. panose and maltotetraose). The hydrolysation results in a hydrolysate. This is filtered to remove insoluble material. It is also typically purified by column chromatography or molecular sieving to remove unwanted sugars.

6.

The purified hydrolysate is then hydrogenated. This converts the sugars into sugar alcohols in the form of a syrup. Hydrogenation of the maltose in the hydrolysate will result in maltitol within the syrup. Hydrogenation of the maltotriose in the hydrolysate will result in maltotriitol within the syrup. The hydrogenated equivalents of other by-products of maltose production are sorbitol, panitol and maltotetraitol. Since the object of the exercise is the production of maltitol crystals, the presence of maltotriitol and other by-products is regarded as an impurity.

7.

The syrup is then crystallised. Even if they are not polymorphic, crystals can grow in different ways, and exhibit different shapes. The different shapes are properly called “habits”. However, the patent in suit describes the different shapes as different “forms”; which is an alternative descriptor. These different habits form as a result of the symmetry of the internal crystal structure and the relative growth rates of the crystal faces. Thus if molecules of maltitol accumulate at one face more rapidly than at another, long needle-like crystals are formed. If, on the other hand, the crystals accumulate at the same rate at the competing faces, the resulting crystals are likely to be more cubic in nature. There is no accepted nomenclature for the different habits that crystals take. Different adjectives are used by different people to describe what is essentially the same habit. Thus Roquette have described the same habit as “bipyramidal”, “arrondi” (round) and “pavé” (like a cobblestone). Others have described the same habit as “parallelepipedal”.”

At the heart of the claim in the patent is the proposition that maltitol crystals can be isolated in two particular forms which have different characteristics and are advantageous for different commercial applications, and that the form of the crystals is a function of the maltotriitol content of the syrup to be subjected to crystallisation.

The patent as originally filed in the European Patent Office contained ten claims. It was objected to (though not by T&L) and the EPO rejected the first nine claims. Roquette appealed against the rejection of the ninth claim, but later abandoned that appeal. So, only the tenth claim stands, but it is common ground that the addressee of the patent is aware of the claims that have been excluded from the patent.

As it stands, the sole claim is as follows:

“The use of maltotriitol to modify or control the form of maltitol crystals.”

The claim must, however, be understood in the context of the patent as a whole. Article 69(1) of the European Patent Convention provides as follows:

“The extent of the protection conferred by a European patent or a European patent application shall be determined by the claims. Nevertheless the description and drawings shall be used to interpret the claims.”

It has to be read in conjunction with article 1 of the Protocol on the interpretation of article 69:

“Article 69 should not be interpreted as meaning that the extent of the protection conferred by a European patent is to be understood as that defined by the strict, literal meaning of the wording used in the claims, the description and drawings being employed only for the purpose of resolving an ambiguity found in the claims. Nor should it be taken to mean that the claims serve only as a guideline and that the actual protection conferred may extend to what, from a consideration of the description and drawings by a person skilled in the art, the patent proprietor has contemplated. On the contrary, it is to be interpreted as defining a position between these extremes which combines a fair protection for the patent proprietor with a reasonable degree of legal certainty for third parties.”

Mr Purvis Q.C., for Roquette, warned us not to be over technical and linguistic in our approach to the construction of the patent, and argued that the judge had erred in this respect, adopting “an over-abstract and linguistic approach which ultimately departed from the whole teaching of the specification”. In an earlier judgment, Virgin Atlantic Airways Ltd v Premium Aircraft Interiors UK Ltd [2009] EWHC 26 (Pat) at paragraph 182(xi), Lewison J concluded a helpful summary of the principles of construction as applied to patents with this proposition, derived from Lord Diplock’s speech in Catnic Components v Hill & Smith [1982] RPC 183:

“Finally purposive construction leads one to eschew the kind of meticulous verbal analysis which lawyers are too often tempted by their training to indulge.”

Mr Purvis reminded us that the patent is to be read as it would be by a skilled reader with relevant knowledge and experience (as to which see paragraphs [17] and [18] below) and with a practical interest in the technology, and that it should be read in a purposive and practical way, the claim extending to what would be understood by such a person to be claimed in the light of the description.

As with almost any question of the construction of a document, a number of different elements in the document provide different indications of its intended scope and meaning. These featured in the respective arguments of Mr Purvis and Mr Birss and were discussed by the judge in his judgment. I will refer to the principal factors relied on after describing the patent.

As originally drawn, the patent in suit said at [0001] that the present invention concerns maltitol crystals of particular forms and crystalline compositions containing them, and it also relates to a particular process for obtaining these crystals and compositions. As amended, it states:

“The present invention concerns the use of maltotriitol to modify or control the form of maltitol crystals.”

It has a priority date of 1997. Its original language was French, but only the English text was debated before us. As with the judge’s description of the basic background, although I will go into some more detail later, I gratefully use the judge’s own summary of the patent, from his paragraphs 20 to 32:

“20.

… The specification begins by introducing maltitol, and explains that it was first presented in syrup form, then in powder form, and that it has been known in crystalline form since 1980. These crystals are anhydrous maltitol which are subject to wide-ranging patent protection on behalf of the HAYASHIBARA company. The specification then describes two forms of processes for crystallisation: the massé technique and crystallisation in water. These are almost the only processes in industrial use. The products obtained by these methods are of very variable crystallinity and not all are particularly well suited to certain applications such as chewing gum or chocolate. It also gives other examples of situations in which crystals produced by these techniques are not satisfactory. The particular defects to which it draws attention are those of not flowing easily, being liable to cake or knot, poor solubility, being bad vehicles for compression and not meeting the criteria for identification and purity set by the different pharmacopoeias [0008].

21.

The problem that Roquette set out to solve is described in [0009]. It sought “to perfect maltitol compositions which do not have the flow, caking, dissolving or compression defects presented by known maltitol powders.” It continues by asserting [0010] that while working to perfect these compositions it “was able to isolate, in a surprising and unexpected way, two particular forms of maltitol crystals, one bipyramidal and the other prismatic.”

22.

The key teaching of the patent is set out in [0011]. It says:

“It has indeed demonstrated that, against all expectation, the form of the maltitol crystals was a function of the maltotriitol content of a maltitol syrup intended for crystallisation. The Applicant company has noted that by controlling the maltotriitol content of a maltitol syrup, it was possible to direct the form of the maltitol crystals towards one or other of the forms or towards a mix of the two forms, when this maltitol syrup is subjected to a crystallisation stage.”

23.

The bipyramidal crystal is described as made up of two regular tetrahedrons of base 50-500µm, to make an octahedron with edge length of 50-500µm. The experts agree that the octahedron is in fact made up of two square pyramids rather than two tetrahedrons. The prismatic crystal is described as consisting of plane faces constituting a tetrahedron and 100-400µm long by 20-100µm wide.

24.

The patent goes on to explain the merits and demerits of the two different habits: [0014] to [0016]. A semi-crystallised mass of maltitol with bipyramidal crystals is more viscous than one with prismatic crystals. The bipyramidal crystal provides a more thickened mass before refining which is useful in the production of chocolate, and a greater consistency of flow which is useful in the production of pharmaceutical coatings etc. On the other hand the prismatic crystal is more compressible and so enables low-crystal content caking in the manufacture of chewing gum centres and the like.

25.

The patent continues with a description of the two crystal habits. At [0027] to [0030] the patent explains that differences in habit are caused by different quantities of maltotriitol. Less than 1% maltotriitol and the crystals are bipyramidal in habit. More than 4% maltotriitol and the crystals are prismatic in habit. Between 1% and 4% and the crystals are a heterogeneous mixture of the two habits. These data are subsequently tabulated at [0077] (although one figure in the table is in the wrong place). At [0034] the patent repeats its key teaching:

“One of the essential characteristics of the invention is therefore to vary the maltotriitol contents of the maltitol syrups to be crystallised while advantageously retaining a reduced content of maltosyl 1,6 maltitol.”

26.

However, although this paragraph teaches that the maltotriitol content of the maltitol syrup can be varied, it also proposes a number of other ways in which the maltotriitol level can be controlled. The patent goes on to explain that the maltotriitol content of the syrup may be controlled either upstream or downstream. It proposes three different ways of controlling the maltotriitol content upstream (all of which result in the ultimate reduction of maltotriitol content) and two different ways of controlling the maltotriitol content downstream (one of which reduces and the other of which increases the maltotriitol content). The upstream methods of controlling the maltotriitol content of the syrup include alteration of the hydrolysate before hydrogenation (e.g. by molecular sieving). At this stage, there is no maltotriitol present in the hydrolysate, because that comes into existence only after hydrogenation. What is present in the hydrolysate at that stage is its forerunner: maltotriose. The patent explains that all these possibilities for controlling the maltotriitol content may be used singly or in combination: [0038].

27.

The patent continues with a long (and largely irrelevant) description of the process by which the syrup is obtained. However, the patent explains ([0047]) that at the first stage of saccharification:

“it is already possible to control the maltotriose content (which after hydrogenation leads to maltotriitol) … by adjusting the amount of maltogenic α-amylase as a function of the maltotriose content and therefore of the form of the maltitol crystals that it is wished to obtain.”

28.

The patent thus teaches that one way of controlling the crystal habit is by adjusting the maltotriose content of the hydrolysate with the result that the amount of maltotriitol content of the syrup after hydrogenation is likewise controlled. This is reflected in [0071] and [0072] of the specification, which explain:

“[0071] According to a first version of the process, a series of steps is applied to the maltitol syrup obtained in the preceding hydrogenation stage as follows

-

possibly carrying out a chromatographic fractionation, known per se, so as to obtain a maltitol rich fraction and a more or less rich maltotriitol fraction as a function of the form of crystals required

-

concentrating the maltitol rich fraction

-

crystallising and separating the formed maltitol crystals

-

recycling the crystallisation mother liquors upstream of the chromatographic fractionation stage

[0072] According to a second version of the process, a series of steps is applied to the maltitol syrup obtained in the preceding hydrogenation stage as follows

- concentrating the maltitol syrup

- crystallising and separating the formed maltitol crystals.”

29.

The first version adjusts the maltotriitol content of the syrup after hydrogenation, but the second version does not. The maltotriitol content has already been determined by the adjustment of the maltotriose content of the hydrolysate; and thus after hydrogenation the syrup merely requires concentration and crystallisation. A similar process is described in [0074] where the maltotriose content of the hydrolysate is again adjusted before hydrogenation.

30.

The patent gives one example to illustrate the claim [0076]. In the example the syrup to be crystallised is concentrated and placed in a dish. Crystallised maltitol is then added, and the dish is cooled. The crystals are thus formed. There is no adjustment to the maltotriitol content of the syrup. The tabular results of the example simply record that “different bases are used”.

31.

As one might expect, the patent culminates in the claims. It is necessary to describe some of the claims that were subsequently abandoned or disallowed by the Opposition Division of the EPO. Claims 1 and 4 as granted claimed the two types of crystal: bipyramidal and prismatic respectively. These claims have been abandoned, because neither of these crystal habits was new. Each had been disclosed by the prior art. Granted claims 2 and 5 claimed compositions comprising those crystals respectively and claim 7 was to a composition comprising both kinds. These claims have also been abandoned for similar reasons. The granted patent also contained claims to processes for making the bipyramidal and prismatic crystals (and mixtures) in claims 3, 6 and 8. Those claims mentioned the maltotriitol content as appropriate (lower than 1% for bipyramidal, more than 4% for prismatic and in between for a mixture). These process claims have also been abandoned because the processes for making crystals using the specified maltotriitol content had also been anticipated by prior art.

32.

Granted claim 9 was:

“A process for directing the form of the maltitol crystals, characterised in that it consists in controlling the maltotriitol content of the maltitol syrup to be crystallised.””

Then the judge explained how it came about that the only surviving claim is the tenth as originally applied for, which I have set out above, at paragraph [8] above.

It is common ground that the skilled addressee of the patent is a team of people interested in the commercial production of maltitol, which includes a chemical engineer with knowledge of carbohydrate chemistry and the different properties of sugars and sweeteners, and someone with knowledge of industrial crystallisation. The team would know that different crystal habits exhibit different performance characteristics, it would know about the relevant industrial process, including the operation of the equipment, and it would have access to relevant textbooks, which the expert witnesses identified. It would have access to an analytic department which would routinely measure the components of the syrup before crystallisation and the habit of the crystals afterwards.

There was also a substantial degree of agreement as to the common general knowledge at the priority date. This included methods of making maltitol, under the most common of which the resulting liquid would be likely to contain not only maltitol but also sorbitol and polyols including maltotriitol. It was known that a number of parameters could influence the rate and extent of crystallisation and the habit of the crystals formed, including temperature, concentration, the presence and rate of stirring and the presence of impurities. Some impurities affected the habit of crystals, others slowed down crystallisation without affecting the habit, while yet others had no effect. The addition of an impurity to a solution intended for crystallisation was a known technique.

The interpretation of the claim in the patent in suit turns on what is meant, in the context, by “use”, “modify or control” and “form”. As to the last, it is not in dispute that it means what is otherwise referred to as the habit of the crystals, in particular here the two contrasting shapes called bipyramidal and prismatic.

The judge considered that the use of the different verbs “modify” and “control” showed that two different activities were referred to. On the one hand, Roquette challenges that reading, and says that it also gives no content to “use”, if “control” can refer to doing no more than checking the composition of the syrup, without changing or affecting it in any way. Mr Purvis submitted that in a case in which that is all that is done, there would be no “use” of maltotriitol, and that this shows that “control” does not necessarily mean anything different from “modify”. He also argued that the claim should be understood as referring to the use of the level of maltotriitol, rather than just the maltotriitol itself.

On the other hand, Mr Purvis also developed an argument before us that “control” and “modify” refer to different stages of the overall process. He said that “modify” refers to a direct alteration in the form of the crystals, which could occur after a first crystallisation, when maltitol crystals already exist, if they are not in the desired form. The form of these could be modified by a re-crystallisation process, in the course of which the level of maltotriitol would be adjusted as necessary. The form of the crystals would be controlled, on the other hand, if the necessary adjustment of the level of maltotriitol were carried out before the first crystallisation. Thus, “control” would refer to something which effected a change, but a change (relevantly) to a future course of events or state of things.

Further, he contended that the “use” of maltotriitol to control the form of the maltitol crystals could include a process applied at the earlier stage, before hydrogenation, when what would be affected directly was the level of maltotriose, but this would lead indirectly to the level of maltotriitol, after hydrogenation, being as desired. It appears that this contention had not been advanced, and had rather been disavowed, before the judge.

Mr Birss had submitted, and the judge accepted, that “modify” and “control” should be taken to refer to different kinds of activity, since otherwise there could have been no reason to use two different verbs. He argued that the terms of the patent required that what was to be used was maltotriitol itself, not, for example, maltotriose, and that therefore Mr Purvis’ position before the judge in that respect had been correct. He contended, both on this basis and because of the terms of the description taken as a whole, that the claim covered a process under which the composition of the syrup was checked, found to contain the appropriate level of maltotriitol, and no further adjustment was carried out. On that basis, he submitted, and the judge accepted, the claim was anticipated.

Because the claim has to be read (as it would be by the skilled addressee) in the context of the description, it is necessary to consider what there is in the description that throws light on the question of construction.

In what the judge described as the key teaching of the patent (see his paragraph 22, quoted at paragraph [15] above) at [0011] the word “control” is first used, in this relevant context: “by controlling the maltotriitol content of a maltitol syrup, it was possible to direct the form of the maltitol crystals towards one or other of the forms or towards a mix of the two forms, when this maltitol syrup is subjected to a crystallisation stage”. It leads on from there, at [0012] (as amended), to the statement that “the invention concerns the use of maltotriitol to modify or control the form of maltitol crystals”. The word “control” there is used in relation to the maltotriitol content, rather than, as in the claim, in relation to the form of the maltitol crystals, but I accept Mr Birss’ submission that, in principle, “control” should be found to be used in the same sense in different parts of the document.

After a description of the different purposes for which one form or the other of the maltitol crystals may be suitable, reference to the particular forms with photographs, and an explanation of the level of maltotriitol content which leads to the production of one of these forms of crystal or the other, or a combination of the two, the patent proceeds at [0034] to identify “an essential characteristic of the invention” as being “to vary the maltotriitol contents of the maltitol syrups to be crystallised”. Mr Purvis relies strongly on the word “vary” in this paragraph, which he contends the judge wrongly ignored.

The word “control” is used again at [0035] (as amended), again in relation to the maltotriitol content:

“To direct the form of the maltitol crystals, the maltotriitol content of the maltitol syrup is controlled. This control of the maltotriitol content of the maltitol syrup to be crystallised may be carried out upstream and/or downstream of the crystallisation stage.”

At [0036] and [0037] it then describes respectively upstream and downstream operations. There are four upstream operations of which two are before hydrogenation and the other two after it. The two downstream operations involve recrystallisation. The second of the downstream operations involves, in terms, the addition of “the amounts of maltotriitol required to obtain, after recrystallisation, a new crystalline maltitol composition complying with the invention with the required maltotriitol content”.

At [0038], referring back to all the operations described in [0036] and [0037], it is said that “all these possibilities for controlling the maltotriitol content may be used singly” or together. Thus, each of these six operations is described as “control”. At [0039], the word “direct” is used again, as previously at [0035]: “the form of the maltitol crystals can be directed”.

The description then sets out a process which, or an equivalent of which, is used to prepare the maltitol syrup “which allows to obtain the composition according to the invention”: [0043]. It refers there to a “controlled hydrolysis”, but that use of the word “control” seems not to add anything either way on the issue we have to consider. In the course of this description, the first part of the saccharification stage is discussed. At [0047] it says that, at this stage, “it is already possible to control the maltotriose content (which after hydrogenation leads to maltotriitol) formed during the hydrolysis of the starch” and it explains how that can be done, “by adjusting the amount of maltogenic α-amylase as a function of the maltotriose content and therefore of the form of the maltitol crystals that it is wished to obtain”. At [0057] it is said that “saccharification is carried out until the maltose hydrolysate contains at least 87%, preferably at least 92% and more preferentially at least 96% by weight of maltose”. If a 96% content of maltose is achieved, then it follows that, after hydrogenation, the maltotriitol content will be less than 4%, and it could be a good deal less, given that there are likely to be other ingredients in the composition as well.

At a later part of the saccharification stage, it is possible, as is explained at [0059], to carry out a stage of maltose crystallisation or molecular sieving. It is said that this process enables “the maltotriose content of the maltose syrup to be controlled, i.e. to more or less deplete, or not at all, the maltose syrup of maltotriose”.

As the judge showed at his paragraphs 28 and 29, the description set out three different possible series of steps to be applied to the maltitol syrup obtained by hydrogenation and a fourth to be applied to the maltose hydrolysate obtained after the earlier saccharification process. At that stage, as it is said at [0074], what could be affected was the level of maltose and maltotriose, not that of maltitol and maltotriitol.

In passing, I note that at paragraph 29 the judge correctly referred to the first three versions, those at [0071] to [0073], as being after hydrogenation and to the fourth, at [0074], as being before hydrogenation. Later at paragraph 40, when he referred back to the second and fourth, he referred to them as if they were both before hydrogenation. That is clearly a slip. He should have referred only to the fourth. Mr Purvis criticised the judge for this, unfairly as it seems to me. Moreover, the point under discussion there was whether the claim applies only if it is the maltotriitol level that is adjusted directly, as Mr Purvis had then argued, not to an adjustment of the level of maltotriose before hydrogenation. Now, as I have mentioned, he has changed his stance and contends that a change to the maltotriose level, which leads to a particular level of maltotriitol, is within the claim.

Then the patent proceeds, as it says, to describe the invention, using a single illustrative example. At [0076] a process of crystallisation is described, in specified conditions, including the addition of a certain quantity of crystallised maltitol. The results, according to “different bases … used”, are set out at [0077]. The table shows that:

After that single example the patent proceeds directly to the claim.

Mr Purvis, in his well-argued submissions, contended that, on the ordinary use of language, “use” suggests an active operation of some kind, and that correspondingly both “modify” and “control” might be expected to signify something active, rather than merely checking or monitoring the position. As I have said, he also contended that “modify” referred to a process applied to maltitol already in crystalline form, whereas “control” referred to taking steps before it was brought into crystalline form.

It is to be remembered that the claim speaks of modifying or controlling the form of the crystals, not of modifying or controlling the maltotriitol, or the level of the maltotriitol. The maltotriitol, or its level, is to be “used” in some way in relation to the form or habit of the maltitol crystals. In the context, it is to be used to secure that the crystals resulting at the end of the process are of one or other of the two habits described in the patent, according to the particular commercial requirements (or, theoretically, a mixture of the two if for some reason that is what is wanted).

As it seems to me, the teaching in the patent is that there are two particular forms of maltitol crystals which have different commercial advantages, that which of them emerges from the crystallisation process is a function of the maltotriitol content of what is subjected to crystallisation, that particular proportions of maltotriitol will lead to one or the other or a combination of the two, and that if what you want is one or the other, you can achieve it by ensuring – if necessary by adjustment in one way or another – that the maltotriitol level is appropriate for your purpose. The adjustment, if needed, can take place before hydrogenation, being applied in that case to the level of maltotriose, or it can take place after hydrogenation, applied to the maltotriitol itself, and if it is done at this later stage, it can be either at the first crystallisation or at a recrystallisation process. That is what seems to me to emerge by way of a natural reading of the patent as a whole.

Mr Purvis presented powerful arguments against the judge’s conclusion. I have already referred to some of them. He argued that the claim is for a process, whereby maltotriitol (or its level) is to be used for a specified purpose, and that if nothing is done to the level of maltotriitol, directly or indirectly, then no process is applied and the invention is not applied in any way, so that it could not be said to be an infringement. It would give no content to the word “use” in relation to maltotriitol, nor would it adequately explain the use of “modify or control”.

It seems to me that the suggested distinction between “modify” as applying to crystalline maltitol whereas “control” applies to the pre-crystallisation stages (whether or not including pre-hydrogenation) does not fit well with [0035] and [0038] which refer to controlling the maltitol content both upstream and downstream of crystallisation. On the other hand, the argument that “control” refers, or can refer, to an active process gains support from those passages and also from [0047].

He also argued that, if read as including a mere checking process, the claim would be altogether too obvious, and would be self-evidently anticipated by prior art which it itself cited, which he said was a position which the skilled reader, who knows about the point of patent law, would not suppose was intended. He showed us the judgment of the Court of Appeal in Virgin Atlantic Airways Ltd v Premium Aircraft Interiors UK Ltd [2009] EWCA Civ 1062, at paragraph 13:

“So the skilled reader is taken to suppose that the patentee knew some patent law – that his claim is for the purpose of defining the monopoly and that it should be for something new. Knowledge of that may well affect how the claim is read – for instance one would not expect the patentee to have used language which covered what he expressly acknowledged was old.”

The judgment deals with the point further at paragraph 21, to similar effect, including this passage:

“because the skilled reader knows that the patentee is trying to claim something which he, the patentee, considers to be new, he will be strongly averse to ascribe to the claim a meaning which covers that which the patentee acknowledges is old.”

Accepting those propositions, the question is nevertheless one of construction, and whether what is claimed is or is not new will depend on, rather than be determinative of, the construction of the claim. There is no rule that because prior art is referred to in the specification, that prior art cannot be found to have anticipated the invention claimed.

Competing submissions were made as to the significance of the outcome of the opposition proceedings and the extensive amendments of the patent resulting from them, which it is common ground the addressee would see. Mr Birss said that, the first nine claims having been eliminated, the reader would be aware that it was legitimate to do what they had claimed as new, and that there was little difference between old claim 9 and the surviving claim 10. On the other hand Mr Purvis submitted that the surviving claim stood on its own terms, and whatever was legitimately within it was protected, whether or not it might have been within claim 9 or some part of one of the other claims. As it seems to me, it is relevant that what survives is a relatively small part of a longer series of claims, but it is not very helpful to consider what might have been the position under the other claims, or some of them. The patent needs to be construed as it stands, with its one claim. Nor do I find it helpful to take account of what was said by any party, or by the EPO, in the opposition proceedings. We have to decide the case before us on its own terms, on the basis of the material and the arguments presented to the judge below and to us.

Mr Purvis emphasised in his submissions that the claim is not to the particular compounds of maltitol which include particular percentages, or percentage ranges, of maltotriitol, but to the use of the maltotriitol element or the level of it. In that, it is said that it differs from some of the abandoned claims, and that it does not claim novelty for something which, as a composition as such, was already known (for example as shown in the Hirao prior art, quoted in the description). The teaching is as to the advantage of the two particular crystalline forms, for particular purposes, and as to this advantage not by itself but in connection with the teaching of a method of arriving at either of these desirable forms.

He argued that the level of maltotriitol is not the only factor which can affect the form of the crystals, and that there is nothing in the claim or the specification that asserts that it is the only determining factor. He referred to paragraph 14 of the judgment in which the judge referred to several possible determinants. On the other hand, there is nothing in the patent which suggests that there is any other factor, and it seems to me that, if the patent is to be taken as teaching the reader how to achieve the particular result, it must be taken to be giving the reader all the information which, taken together with the common general knowledge, is required to ensure that the result is achieved.

Mr Purvis’ point that on the judge’s construction the patent is self-defeating, so to speak, has some force. Such a situation is not what the skilled reader would expect. However, while avoiding the danger of being over-technical and semantic, the skilled reader has to read the language of the patent in a fair way, having regard to all of its contents. He might well be led by [0034] to expect that the claim would involve changing the level of maltotriitol. The claim does not use the word “vary”, however, and although “modify” is a synonym for “vary”, “control” is not necessarily so. What he finds is that, first, “control” is spoken of at [0035] as covering several different types of process, carried out at different stages. Secondly, “control” of the maltotriose content is referred to at [0047], in relation to adjusting the maltotriose content, and specifically in relation to the form of the eventual crystals. Then, at [0059], reference is again made to the maltotriose content, and to it being “controlled”, that is to say being reduced (depleted) to a greater or lesser extent “or not at all”. Next, at [0071] to [0074], four different versions of the process are explained, of which one occurs before hydrogenation (thus, in relation to maltotriose, not to maltotriitol) and one does not involve any adjustment of the level of maltotriitol. Lastly, when he comes to the one and only illustrative example of the invention, at [0076] to [0077], no adjustment is mentioned at all.

It seems to follow from the terms of that example that the invention asserted can be carried out without any adjustment being made, either of the level of maltotriose before hydrogenation, or of that of maltotriitol afterwards. If so, it also appears to follow in turn that an undertaking which does carry out the steps described in the example, without any relevant adjustment, would infringe the patent, regardless of whether it was aware of the patent. Mr Purvis argued that such an undertaking would not “use” the level of maltotriitol, but I find it difficult to see how one could distinguish between a process which, informed by a reading of the patent, did use the level of maltotriitol for the relevant purpose, even though as a result of analysis it found that it was not necessary to make any adjustment of the level, on the one hand, and another which did exactly the same without knowing of the patent.

It seems to me that the combined effect of those various passages and references compel the conclusion that the invention as claimed does not necessarily involve an adjustment to the level of maltotriitol. It includes a case in which the composition is analysed, the maltotriitol content (actually or prospectively via maltotriose) is found to be suitable for the desired outcome, and therefore no adjustment of the level is carried out.

Mr Purvis criticised a passage in the judgment at paragraph 39 where, in discussing the meaning of the word “control”, the judge drew on analogies, one with a mixer tap, another with the running of motor cars, and the third with a French ticket inspector. It does not seem to me that anything turns on these analogies that cannot be derived from the language of the patent itself. I would not rely on them myself, but I do not regard the judge’s observations in this passage as vitiating his conclusion.

In any event Mr Purvis’ development of his argument in ways not put to the judge, both so as to focus on operations before (“control”) and after (“modify”) the first crystallisation, and his contention that an adjustment of the maltotriose level, before hydrogenation, is within the claim, calls for the fresh examination of the material.

I am content to assume that the claim does include a process whereby what is adjusted (if anything is) is the maltotriose content, that is to say before hydrogenation. It is notable that Mr Purvis did not put this argument forward before the judge, but it seems to me to be possible to read the “use” of the maltotriitol as including the use of its forerunner, the maltotriose which, upon hydrogenation, becomes maltotriitol. In this I am particularly influenced by the text of [0047].

Nevertheless, I have come to the same conclusion as the judge, upon the (partly) different arguments put to us, that the skilled reader would conclude that what was being described included not only the case where the level of maltotriitol is not that which is desired, so that it has to be adjusted, but also the case in which the analysis shows that it is suitable, and can therefore be left alone. This does not attach to the use of the word “vary” in [0034] in the patent as much weight as Mr Purvis would have us do, where to “vary” the maltotriitol contents of the maltitol syrup is said to be one of the essential characteristics of the invention. On the other hand, when the description moves into the detail of the process, it speaks in terms, at [0059], of depleting the maltotriose content of the maltitol syrup more or less “or not at all”. Moreover, the process described at [0072], after hydrogenation, does not involve any adjustment of the maltotriitol content. Nor does the single illustrative example of the invention, given at [0076-0077], involve any adjustment either of the maltotriitol content or, earlier, of the level of maltotriose. How the reader is to be expected to conclude that the claim in the patent does not include a case which represents one of the four series of steps given as different versions of the process, and where the sole illustrative example of the invention can be followed without carrying out any adjustment, I find difficult to understand. Mr Purvis’ eloquence has not persuaded me that the formulation of these concrete examples should give way to the language of [0034] with the word “vary”, or to any assumption, whether based on the reference to prior art, or on what was said in the Virgin Airways case or otherwise, by which what seems to me to be the natural reading of the patent should be taken as limited to processes in which there is an adjustment of the level, whether of maltotriose before hydrogenation or of maltotriitol afterwards.

Accordingly, I conclude that the judge was right in his construction of the patent in suit, and I would therefore dismiss the appeal. I find it unnecessary to deal with the other issues on the Appellant’s Notice, nor will it be necessary to consider the Respondent’s Notice.

I agree.

I also agree.