Section 125

Extent of invention

Previous Index Next

125.-(1) For the purposes of this Act an invention for a patent for which an application has been made or for which a patent has been granted shall, unless the context otherwise requires, be taken to be that specified in a claim of the specification of the application or patent, as the case may be, as interpreted by the description and any drawings contained in that specification, and the extent of the protection conferred by a patent or application for a patent shall be determined accordingly.

(2) It is hereby declared for the avoidance of doubt that where more than one invention is specified in any such claim, each invention may have a different priority date under section 5 above.

(3) The Protocol on the Interpretation of Article 69 of the European Patent Convention (which Article contains a provision corresponding to subsection (1) above) shall, as for the time being in force, apply for the purposes of subsection (1) above as it applies for the purposes of that Article.

Manual of Patent Practice

The 'Improver/Protocol Questions':

Improver Corporation v Remington Consumer Products Limited [1990] FSR 181, p189:

  • (1) Does the variant have a material effect upon the way the invention works? If yes, the variant is outside the claim. If no-
  • (2) Would this (i.e. that the variant had no material effect) have been obvious at the date of the publication of the patent to a reader skilled in the art. If no, the variant is outside the claim. If yes -
  • (3) Would the reader skilled in the art nevertheless have understood from the language of the claim that the patentee intended that strict compliance with the primary meaning was an essential requirement of the invention. If yes, the variant is outside the claim.
  • On the other hand, a negative answer to the last question would lead to the conclusion that the patentee was intending the word or phrase to have not a literal but a figurative meaning (the figure being a form of synecdoche or metonymy) denoting a class of things which included the variant and the literal meaning, the latter meaning, the latter being perhaps the most perfect, best-known or striking example of the class.

Wheatley v Drillsafe [2000] EWCA Civ 231, para 23:

  • "As the task of the court is to ascertain objectively what meaning the words were intended to convey, the Improver questions, better called the Protocol questions, were proposed as an aid. It is reasonable to infer, absent express words to the contrary, that the patentee intended to include within his monopoly what can be termed immaterial variants, in the sense that they were not material to the way the invention worked. Also it is reasonable to infer that a patentee did not intend to include within the ambit of his monopoly a variant which had a material effect upon the way the invention worked, otherwise his claims could, to the detriment of the patentee, include variants which had little if anything to do with what he had invented. However third parties have to be considered and therefore they should not be held to infringe if it was clear that such a variant was not intended to be within the ambit of the monopoly either because of the words chosen or because it would be seen to have materially affected the way the invention worked."

Merck v Generics (UK) Ltd [2003] EWHC 2842 (Pat), at para 50:

  • "How does this approach marry up with the Improver questions? As the Court of Appeal said in Pharmacia, the Improver questions are "normally useful tools" but they may not be easy or appropriate to apply in every case. In the end one must return to look at the Protocol itself. There is nothing to suggest that Hoffmann J intended to put the three questions forward as a rigid checklist with three boxes, each of which needs to be ticked appropriately for there to be infringement. The Improver questions may well provide a useful structured approach to the issue of infringement, just as the Windsurfing test does in relation to obviousness. They are not a substitute for the Protocol".

Kirin Amgen v Hoechst Marrion Roussel [2004] UKHL 46 (at para 34):

  • "'Purposive construction' does not mean that one is extending or going beyond the definition of the technical matter for which the patentee seeks protection in the claims. The question is always what the person skilled in the art would have understood the patentee to be using the language of the claim to mean. And for this purpose, the language he has chosen is usually of critical importance. The conventions of word meaning and syntax enable us to express our meanings with great accuracy and subtlety and the skilled man will ordinarily assume that the patentee has chosen his language accordingly. As a number of judges have pointed out, the specification is a unilateral document in words of the patentee's own choosing. Furthermore, the words will usually have been chosen upon skilled advice. The specification is not a document inter rusticos for which broad allowances must be made. On the other hand, it must be recognised that the patentee is trying to describe something which, at any rate in his opinion, is new; which has not existed before and of which there may be no generally accepted definition. There will be occasions upon which it will be obvious to the skilled man that the patentee must in some respect have departed from conventional use of language or included in his description of the invention some element which he did not mean to be essential. But one would not expect that to happen very often."

at para 52:

  • "These questions, which the Court of Appeal in Wheatly v Drillsafe Ltd [2001] RPC 133, 142 dubbed "the Protocol questions" have been used by English courts for the past fifteen years as a framework for deciding whether equivalents fall within the scope of the claims. On the whole, the judges appear to have been comfortable with the results, although some of the cases have exposed the limitations of the method. When speaking of the "Catnic principle" it is important to distinguish between, on the one hand, the principle of purposive construction which I have said gives effect to the requirements of the Protocol, and on the other hand, the guidelines for applying that principle to equivalents, which are encapsulated in the Protocol questions. The former is the bedrock of patent construction, universally applicable. The latter are only guidelines, more useful in some cases than in others. I am bound to say that the cases show a tendency for counsel to treat the Protocol questions as legal rules rather than guides which will in appropriate cases help to decide what the skilled man would have understood the patentee to mean. The limits to the value of the guidelines are perhaps most clearly illustrated by the present case and therefore, instead of discussing the principles in the abstract as I have been doing so far, I shall make my comments by reference to the facts of the case."

See also Rockwater Ltd v Technip France SA at para 41

Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License