David Parsons v Convatec Limited

In proceedings under section 40(1) of the Patents Act 1977, an invention is not identified by a mechanical, claim-by-claim construction of the granted patent. Section 125(1) concerns the extent of patent protection and does not invariably determine the inventive concept relevant to employee compensation.

The invention must instead be identified objectively from the information in the relevant specification, while maintaining a clear link to the patent said to have been granted for it. Pleadings must refer to specific parts of the patent or application, including the description and at least one representative claim. Procedural shortcomings did not prevent the court from giving directions under the overriding objective.

Dr Parsons, a chemist employed by Convatec for about 30 years, brought a claim for employee compensation under section 40(1) of the Patents Act 1977. His amended particulars identified groups of inventions by technical field and referred to patent families, but did not link the pleaded inventive concepts to specific parts of the patents.

Convatec sought further information, including identification of claims and inventive concepts, so that it could plead its defence. Dr Parsons contended that a claim-by-claim approach was unnecessary and that Convatec should amend its defence. The central issue was how an invention should be identified and pleaded in section 40(1) proceedings.

1. Procedural approach. The court could address the substance of the parties’ procedural impasse and give directions despite the absence of a separate Part 23 application by Dr Parsons and the procedural objections concerning Part 18. This was consistent with active case management and CPR 1.4.
2. Meaning of invention. Section 125(1) was the starting point, but its context concerns the scope of protection conferred by patent claims. Section 40(1) draws a distinction between the invention and the patent subsequently granted for it. The invention therefore need not be identified solely by scrutinising the claims ultimately granted.
3. The guidance in Markem Corp v Zipher Ltd [2005] EWCA Civ 267 was applicable. A claim-by-claim approach was inappropriate. The invention should be identified from the information in the specification, rather than from the specific form of the claims. Nevertheless, it had to be objectively identified by reference to the relevant patent or patents and clearly linked to the patent granted for the invention.
4. Pleading directions. The amended particulars were insufficient because they grouped inventions by technical field and patent family without identifying the relevant material in the specifications. Dr Parsons was directed to amend the pleadings by clear reference to specific parts of the relevant patents or applications, including at least the description and at least one representative claim. Convatec would then need to prepare an amended defence taking those amendments into account.
5. Post-judgment corrections. The circulation of a draft judgment is principally for correcting typographical or similar errors. A party proposing substantive changes should immediately inform the other party. The court made minor clarifications after reviewing the draft, while discouraging attempts to reopen or reargue the case.

First-instance case. The judgment records earlier interlocutory proceedings in the same litigation, including the decision of Zacaroli J in Parsons v Convatec Ltd [2023] EWHC 1535 (Pat).