TQ Delta, LLC v Zyxel Communications UK Ltd & Anor

Applications concerning expert evidence and amendments are assessed under the overriding objective. Lateness is a relevant factor, but the court must assess the practical consequences of the proposed evidence and the prejudice to the other party.

A party may generally substitute an expert whom it no longer wishes to rely upon, particularly where the replacement expert is within the scope of the existing permission. A late new argument may nevertheless be refused where it would require substantial additional factual, disclosure and expert work, especially if it could have been pleaded earlier.

The defendants sought permission to rely on an additional sector expert, to substitute a financial expert, to amend their RAND case to introduce an SSPPU argument, to enlarge the confidentiality club and to extend time for expert evidence.

The applications arose in patent infringement proceedings involving a technical trial, a pending RAND trial and a damages inquiry. The court considered whether the proposed evidence and amendment could fairly be admitted at the procedural stage reached, and whether the replacement financial expert should be permitted to rely on material from the former expert.

1. Additional sector expert. The application to rely on Dr Peeters was dismissed. The relevant approach required assessment under the overriding objective, with the lateness of the application being a material factor. The defendants had known for several months of the September RAND trial and had not produced the proposed report. The court could not properly assess its necessity, scope or effect on the timetable. The likely need for responsive evidence and the limited availability of existing experts also weighed against permission. The question of extending time therefore did not arise.
2. Substitution of financial expert. Permission was granted for Dr Lynde to replace Mr Pampinella. The existing order permitted financial expert evidence without restricting the particular financial expertise. Refusing substitution would have forced the defendants to rely on an expert they no longer wished to use. There was no suggestion of expert shopping. Dr Lynde had been transparent about using the earlier report, and criticisms concerning leading, source material and cross-examination could be addressed at trial. The claimant had no proprietary right in the former expert.
3. SSPPU amendment. The proposed section 5.3 argument was refused and the relevant paragraphs were struck out. Although the argument appeared capable of succeeding, it could have been pleaded much earlier and was raised only because the new expert identified it. It would require materially different factual investigations, disclosure and expert evidence. Its inclusion in a pleading for the parallel damages inquiry could not operate as a means of introducing a substantial new case into the RAND trial at a late stage.
4. Confidentiality club. Permission was granted to add individuals assisting Dr Lynde. The evidence showed that he was hindered by the lack of assistance in a substantial exercise, while those receiving access would understand their confidentiality obligations.

The judgment is a first-instance decision on interlocutory applications in patent proceedings. The judgment records that a separate decision of Birss J concerning disposal of the RAND trial was subject to an appeal, but that appeal was not determined in this judgment.