In an earlier judgment in the case referred to above, the parties' respective experts had arranged to have a joint discussion. It subsequently became apparent to the defendant's expert (when an email was sent to him in error) that the claimant's expert had been seeking advice from one of her colleagues about certain points in the experts' joint statement. An issue then arose as to whether the discussions between the expert and her colleague were privileged.

The claimant's expert had informed the court that her firm has a peer supervision arrangement in place. The judge said that if it is becoming commonplace for there to be undisclosed arrangements in relation to "supervision" in the preparation of expert evidence (and, in particular, supervision which may alter the content of the report) that is "a very worrying development". He highlighted the importance of disclosing to the court and the other side if the expert's evidence has been "bolstered or added to" by a third party. PD 35 para 9.8  provides that "If an expert significantly alters an opinion, the joint statement must include a note or addendum by that expert explaining the change of opinion". The judge said that that should include adding whether or not the change comes as a result of information provided by another expert.

It was held that communications between an expert and a third party (other than the expert on the other side) are not privileged. The judge concluded that "Any expert who discusses the content of a proposed report in detail with another expert under a peer review arrangement must be extremely cautious if he or she thinks it is not appropriate to disclose the fact and extent of that arrangement. Indeed, I would go as far as to say the circumstances in which he or she cannot properly do so must be very limited indeed".

COMMENT: When instructing experts, a party should clarify who, in addition to the expert, might be involved in the preparation of the expert’s report and remind the expert to check and adopt the analysis or conclusions of anyone he has delegated work to. This case is a reminder to also check, where the expert works as part of a group practice, whether a peer supervision or review arrangement is in place, especially since communications between the expert and his/her supervisor will not be privileged.