A recent decision illustrates how the court will exercise its discretion in considering whether to grant permission to substitute a new expert, and whether to require the disclosure of draft reports and other documents as a condition of granting permission: Avantage (Cheshire) Ltd v GB Building Solutions Ltd [2023] EWHC 802 (TCC).

It is well established that the court can, and normally will, require a party to waive privilege in a previous expert's report where it grants permission to change experts, and may in some circumstances order disclosure of other documents prepared by the expert or recording their views. While the court cannot override privilege, it can impose such a condition as the "price" of granting permission.

The present case is of interest in illustrating the courts' approach where claimants sought to substitute two of their experts with a single new expert. In the first case the previous expert was too ill to continue. In the second case the expert was able to continue but the claimants did not have confidence in the expert.

The court granted permission for the substitution in both cases but took a different approach to imposing conditions. In the first case, as there was no hint of expert shopping, there was no need to disclose the previous expert's reports or other documents recording their views. However, as the previous expert had inspected the relevant (now demolished) property shortly after the incident in question, the court ordered disclosure of that expert's notes of site visits and interviews with factual witnesses. Fairness and transparency required that this material should be made available to all the relevant experts in the case.

In the second case, the court allowed substitution of the expert despite the defendants' legitimate concerns about expert shopping. However, permission was granted on the condition of disclosure of the previous expert's reports (including drafts) and other documents he had prepared expressing his opinions – but not attendance notes prepared by the claimants' solicitors.

The decision arguably takes a more flexible view of the need for a "good reason" for a change of expert than some previous decisions (see for example this blog post). In this case the court granted permission for the substitution of the second expert on the basis that the claimants were not happy with the expert and should be able to rely on an expert in whom they had confidence. The courts may not always consider that this is sufficient, particularly where a change of expert is sought at a late stage. Each case will turn on its facts.

Background

Following a fire at a retirement village, the developer, freeholder and leaseholder of the property brought proceedings against the contractors and consultants engaged in its construction, alleging deficiencies in design and construction which they said had resulted in the spread of the fire. The claimants had permission to call various expert witnesses including a forensic scientist, Ms H, to give evidence on the cause, origin and spread of the fire, and a fire engineer, Mr W, to give evidence on whether the design of the property complied with the Building Regulations and whether the design should have included sprinklers.

The claimants applied to substitute Ms H with another expert, Dr K, on the grounds that Ms H was seriously unwell and required medical treatment. The defendants did not oppose the application in principle but argued that the substitution should be made on the condition that the claimants be required to disclose Ms H's expert reports (draft and final versions), site inspection notes, notes of any witness interviews, and any other documents evidencing her opinion on the cause, origin or spread of the fire including attendance notes produced by the claimants' solicitors.

The claimants also applied to call Dr K in place of Mr W, on the grounds that they were unhappy with Mr W as an expert and there was a potential for conflict between his views and the claimants' other experts dealing with overlapping areas. The defendants opposed the application on the basis that it was expert shopping, and argued in the alternative that if permission was granted it should be on condition of disclosure of Mr W's expert reports (including drafts) and any other documents evidencing his opinions, including attendance notes.

Decision

The High Court (O'Farrell J) granted both applications on condition that certain documents be disclosed, but not all of those sought by the defendants.

The judge referred to The University of Manchester v. John McAslan & Partner [2022] EWHC 2750 (TCC) (considered here) for its helpful review of the authorities. She summarised the relevant principles, including the following:

  • The court has a general discretion to permit a party to substitute a new expert witness, pursuant to its specific power to control the use of the expert evidence under CPR 35.4 or as part of its general case management powers under CPR 3.1(2). The usual rule is that such permission should not be refused.
  • The court has the power to grant permission on condition that the original expert's reports are disclosed to the other party. Such a condition is usually, to prevent expert shopping and ensure that the expert's contribution is available to the court and all parties.
  • The court's power to impose conditions may extend to other documents containing the substance of the original expert's opinion but the court must be cautious about encroaching on areas of privilege and consider carefully the potential value of such other documents. In particular, there must be a strong case to justify disclosure of solicitors' attendance notes.

Applying these principles, the judge noted that the claimants had been forced to replace Ms H due to reasons beyond their control, and there was no question of expert shopping. It would therefore be unjust to order the claimants to disclose her reports, draft reports or other documents setting out her opinion. However, she accepted the defendants' argument that Ms H had conducted site inspections and investigations shortly after the fire and would have gathered relevant primary evidence regarding the condition of the property and the presence of defects. As the property had since been demolished, such information would no longer be available to other experts. Similarly, her notes of an interview with a neighbouring resident could contain details that might be significant to the experts but which the witness did not see as significant, or did not recall, and which would therefore not be addressed in his statement. Accordingly, as a matter of transparency and fairness, the court ordered the claimants to disclose all early inspection notes and witness interviews conducted by Ms H.

Regarding Mr W, the judge noted the defendants' legitimate concerns that the application seemed to be an exercise in expert shopping. However, she was satisfied that, in the interests of justice, the claimants should be given permission to rely on an expert in whom they had confidence. The order was made on the condition that Mr W's reports (including drafts), and any other documents he had prepared expressing opinions on the dispute, should be disclosed. However, the judge did not consider that the claimants should be required to disclose their solicitors' attendance notes. In the absence of any suggestion of culpable behaviour on the part of the claimants, who were simply unhappy with Mr W as an expert, such an order would constitute an unnecessary invasion of the claimants' privilege.

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