How will the Court deal with requests to change expert witnesses?

In Avantage (Cheshire) Ltd v GB Building Solutions Ltd & Ors [2023] EWHC 802 (TCC), the High Court gave guidance on its approach when a party seeks permission to change experts and the circumstances relevant to whether disclosure of prior reports or other documents will be required.

Background

The claim arose out of a fire that occurred at a retirement village in 2019, which destroyed almost the entire property. The claimants were the property owners and the developer. The defendants were contractors and consultants involved in the construction of the property. The claimants sought substantial damages on the basis that alleged deficiencies in the design and construction of the property caused the spread of the fire.

At the case management conference, the claimants were given permission to rely on four expert witnesses. They included:

1. Ms H – a forensic scientist, hired to give evidence in relation to the cause, origin and spread of the fire; and
2. Mr W – a fire engineer, hired to give evidence as to the adequacy of the fire strategy, and building regulations.

Due to ill health, Ms H was unable to continue her role as an expert. The claimants made an application seeking the court’s permission to replace Ms H with an alternative expert, Dr K. The claimants also applied to replace Mr W with Dr K.

The court’s powers in relation to experts

The court has general management powers in relation to expert evidence under Part 35 of the Civil Procedure Rules. The principles relevant to the court’s power to permit a party to change an expert witness were recently summarised in The University of Manchester v John McAslan & Partner and others [2022] EWHC 2750 (TCC), which held that:

• The court has a general discretion to permit a party to change the identity of the expert pursuant to CPR 35.4 and/or CPR 3.1(2). This discretion should be exercised having regard to all the material circumstances of the case and in accordance with the overriding objective;
• The usual rule is that a court should not refuse a party permission to rely on a new expert in substitution for an existing expert; and
• In order to prevent expert shopping and ensure that the original expert’s contribution is available to the court and all parties, the court may impose a condition requiring that the original expert’s reports containing the substance of the expert’s opinion are disclosed to the other parties. This power also extends to other documents containing the substance of the original expert’s opinion, but the court must be cautious about encroaching on areas of privilege. In particular, there must be a strong case to justify disclosure of solicitors’ attendance notes.

Ms H (substitution on the grounds of ill health)

The defendants did not contest that the claimants were entitled to replace Ms H with Dr K because she could no longer attend the trial due to ill health. However, the defendants requested that Ms H’s expert reports, site  inspection reports and interview notes were disclosed. The court held that, given there was no question of expert shopping, it would be unjust to require that the expert’s reports be disclosed as a precondition of the court’s permission. However the court determined that the site inspection reports and interview notes should be disclosed.  These documents contained evidence of primary facts,in particular the condition of the building in the aftermath of the fire. The  building had since been demolished, so further inspections could not be conducted.  It is also likely that the new expert would have access to these documents and use them to inform his or her opinion.

Mr W (substitution on the grounds of loss of confidence)

The claimants also applied to replace Mr W with Dr K (i.e. the same expert who would be replacing Ms H). The claimants’ grounds were that Mr W had given views which overlapped with other experts’ opinions (i.e. there was potential for conflict) and that the claimants felt that Mr W had not done a full review of the supporting documents. The claimants’ counsel confirmed in submissions that the claimants were not happy with Mr W as their expert. The defendants opposed the application on the basis that insufficient grounds had been given to replace Mr W, or alternatively that any permission should be conditioned on disclosure of draft expert reports, other documents where Mr W expressed opinions about the dispute and solicitors’ attendance notes of discussions with Mr W.

The court agreed that the claimants’ application appeared to be expert shopping. However, the judge held that “It is in the interests of justice that the claimants should have permission to rely on an expert in whom they have confidence” and that, due to an adjournment to the trial, no prejudice would be suffered by the change of expert.

The claimants accepted that Mr W’s draft reports must be disclosed. The court also ordered disclosure of other documents where Mr W expressed an opinion on relevant matters. The court, however, stopped short of requiring solicitors’ attendance notes of discussions with Mr W to be disclosed. It considered that the documents would have little probative value once necessary redactions to protect privilege were applied. Further, this would be an unnecessary invasion of the claimants’ privilege where there had been no suggestion of culpable behaviour by the claimants or their experts.

Key takeaways and comment

This case provides useful guidance in relation to the principles that the courts will apply to applications to change an expert witness and related disclosure issues. It illustrates how the courts will resolve the competing interests of, on the one hand, experts’ independence and duties to the court and, on the other, the fact that a party is entitled to choose its expert.

Selecting an expert is often a key strategic decision in litigation. In this case, although one of the changes of expert was beyond the claimants’ control, the other was due to loss of confidence which appeared to emerge after the court gave the claimants permission to call the expert as a testifying expert. Although the claimants were entitled to change this expert, notwithstanding that they appeared to be engaging in ‘expert shopping’, the price paid was disclosure of the original  expert’s draft reports/opinions. For this reason, parties should always endeavour to explore fully their options for experts, testing the expertise of potential candidates prior to designating them as such.

With thanks to Holly Tunnah for her assistance in preparing this post.