David Parsons v Convatec Limited

For a claim under section 40 of the Patents Act 1977, the invention, rather than the patent, must belong to the employer. The employee need not be named as inventor in the patent. The statutory prescribed period is a limitation period which forms a self-contained regime and displaces section 9 of the Limitation Act 1980, even though the court may extend it. Benefit may arise from a patent without the invention being used in a marketed product. A late extension requires sufficient reason, assessed in all the circumstances, including the protection which the prescribed period gives the employer against stale claims. The court refused to extend time where the delay was substantial and unexplained.

Dr David Parsons, an analytical chemist employed by Convatec Limited from 1991 to 2022, claimed compensation under section 40 of the Patents Act 1977 for inventions concerning antimicrobial dressings and related products. Convatec applied to strike out or obtain summary judgment on parts of the claim, accepting for the application that Dr Parsons had made the inventions and that the relevant patents or inventions were of outstanding benefit.

The issues included whether the patent had to have been granted to Convatec, whether Dr Parsons had to be named as inventor, whether section 9 of the Limitation Act 1980 applied, whether a patent not used in a marketed product could generate outstanding benefit, whether alleged prior use justified strike-out, and whether time should be extended for two revoked European patents.

1. Strike-out and summary judgment. The court applied the principles summarised in Easyair Ltd v Opal Telecom Ltd [2009] EWHC 339 (Ch). Pleaded facts were assumed in the claimant’s favour where disputed. The court should not conduct a mini-trial, but should decide a short point of law where the evidence is sufficient and the parties have had a proper opportunity to address it.
2. Requirements under section 40. Section 40 requires the invention to belong to the employer as between employer and employee. It does not require the patent to have been granted to the employer. Nor does it require the employee to be named as inventor. The register is only prima facie evidence, and the statutory provisions recognising an inventor’s right to be mentioned, and the right to waive that mention, are inconsistent with such a requirement.
3. Limitation. Section 9 of the Limitation Act 1980 does not apply. The prescribed period under section 40, defined through CPR 63.12 and Rule 91 of the Patents Rules 2007, is a limitation period prescribed under another enactment. It therefore displaces the general limitation provisions. The possibility of extension does not alter that conclusion. The claim concerns compensation assessed by reference to the benefit derived from the invention or patent, rather than recovery of particular benefits accruing in separate periods.
4. Outstanding benefit and validity. Non-use of an invention in a marketed product does not itself prevent a patent from generating outstanding benefit. Market exclusion, increased prices or market share, and successfully defending the patent may be relevant. The alleged prior disclosure raised factual issues for trial. A patent’s possible invalidity did not itself bar a section 40 claim, particularly in light of section 43(5A), which excludes benefit derived after revocation but implies that pre-revocation benefit may be relevant.
5. Extension of time. The court had an unfettered but principled discretion. The claimant gave no evidence explaining the failure to bring the claims within the prescribed periods or the subsequent delay. The proposed extension was very substantial. The employer’s substantive protection against liability many years after the event outweighed the limited procedural benefit of dealing with the claims at the same trial. Prejudice from being time-barred and general asymmetry of resources were insufficient. Time was not extended, and the claims concerning EP1343510 and EP1539070 were struck out.