Expert evidence requirements “not optional extras”

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Permission of the court is required for expert evidence and the court has a duty to restrict it to that which is reasonably required to resolve the proceedings. In addition, an expert must comply with the requirements of Part 35 of the Civil Procedure Rules (CPR) and the associated Practice Direction.

The decision in R (Good Law Project Ltd) v Secretary of State for Health and Social Care) [1] serves as a cautionary reminder to experts, and the advisers instructing them, of the importance of fully familiarising themselves with the requirements and complying with them. The court refused the Secretary of State’s application to adduce expert evidence in a judicial review claim due to a widespread failure to observe the requirements, in particular that experts for both parties must have access to the same material.

The court stressed that the requirements are not optional extras, only to be complied with by a litigant and their expert if the court states in a specific case that they are to apply. There is no excuse for litigants to fail to comply with the rules generally, nor for failures by experts to comply with the requirements of CPR Part 35 specifically. Parties in judicial review proceedings are not entitled to some wider indulgence, nor are the rules to be applied less strictly simply because a case concerns public law. The court also noted that there is a duty of candour in judicial review proceedings generally. See our separate briefing for details.

[1] [2021] EWHC 2595 (TCC)