SafeStand Limited v Weston Homes PLC & Ors.

Where a party deploys litigation experiments, privilege in related experimental material is not waived automatically. The court must identify the issue or transaction for which the experiments are deployed and adopt a cautious, restrictive and fact-sensitive approach. Disclosure may nevertheless be required where withholding related experiments risks unfairness or misunderstanding of the evidence.

In patent proceedings, the relevant material may include experiments using different protocols or product parameters where they bear on the consistency and meaning of the technical proposition advanced. Any order must remain suitably circumscribed and satisfy necessity, reasonableness and proportionality. The court may also order specific disclosure under Practice Direction 57AD or its general case-management powers, notwithstanding a patent product and process description.

The claimant brought patent-infringement proceedings concerning trestle systems, together with claims concerning re-registered design rights. The defendants sought permission to rely on three experiments addressing the relative longitudinal stability of their products and conventional trestles. The claimant did not oppose that application.

The claimant also sought specific disclosure of reports and data concerning those experiments, including related experiments involving products of different heights. The principal questions were whether reliance on the amended notice of experiments resulted in an implied or consequential waiver of privilege, and whether further disclosure was necessary, reasonable and proportionate under the applicable disclosure regime.

1. Permission to rely on experiments. The defendants were permitted to rely on Experiments 1 to 3 and the report of the witnessed repeats. The experiments appeared to have probative value and had been foreshadowed, repeated and addressed in expert evidence. No conditional order linking permission to the claimant’s disclosure application was required.
2. Jurisdiction. The court had jurisdiction to order specific disclosure under paragraph 18 of Practice Direction 57AD. Its general case-management jurisdiction, preserved by paragraph 20, provided an alternative basis. The patent-specific provisions in Practice Direction 63 did not fetter that jurisdiction.
3. Waiver. Implied or consequential waiver of privilege required a relatively cautious and restrictive approach. The court had to identify the issue or transaction addressed by the deployment, determine the scope of the representations thereby made, and consider whether withholding further material would cause unfairness or misunderstanding. The analysis was fact-sensitive and extended only so far as necessary.
4. The amended notice of experiments was deployed to demonstrate a relative difference in longitudinal stability between the defendants’ products, or variants such as products of different heights, and the trestles. Related experiments addressing that issue could therefore form part of the same transaction. Their disclosure was required if they existed, even where their protocol was not identical to the deployed experiments. The same conclusion applied to non-infringement by normal construction and by equivalents.
5. The requested disclosure was sufficiently specific and potentially probative. It was necessary for the just disposal of the proceedings and reasonable and proportionate, having regard to the issues, likely evidential value, limited search, expense and importance of avoiding an unfair presentation of experimental evidence.
6. The defendants were ordered to provide a compliant version of the relevant report removing redactions of irrelevant material that was not confidential, and to give an appropriately detailed explanation of any privileged material remaining.

The judgment was a first-instance decision on interlocutory applications in patent-infringement proceedings. The judgment records earlier case-management and disclosure directions made by Mann J and Marcus Smith J, but no appeal from an earlier decision is described.