[2024] EWCA Civ 609
This was a case where the Competition Appeal Tribunal ("CAT") ruled that the defendants' economic expert evidence should be given by a single expert shared between the three (now two) groups of defendants involved. The CA rejected an appeal against that ruling on the grounds that there was a conflict of interest between the defendant groups.
Even though the single joint expert ("SJE") is rarely used in construction cases, often because experts are instructed at an early stage of any dispute, the case is interesting for the comments made by the CA about the principles applying to the use of the SJE.
The parties both proceeded on the basis that there was no relevant difference between the principles applicable to expert evidence in the CAT and the civil courts of England and Wales under the CPR. SJEs can be instructed by both sides or, as here, an SJE can be instructed by distinct groups of defendants. Birss LJ considered that a court direction for an SJE to give evidence in place of separate experts from distinct parties in the proceedings, like any other direction giving permission for expert evidence, was governed by two primary dimensions. One is the overriding objective – namely, that the court will seek to ensure that the case is dealt with justly and at proportionate cost. The other is the duty to restrict expert evidence – in other words, to limit it to that which is reasonably required to resolve the proceedings in issue.
Often, SJEs are considered in the context of low value cases when proportionality is important. However, the same principles apply irrespective of the value at stake. The SJE will often be appointed where the claimant and the defendant have what the judge described as a "manifest" conflict of interest, not just in the case overall but in relation to the very matter on which the single joint expert will express an opinion. However, ultimately, the SJE, whose overriding duty is to the court, will come to their own view of the issue.
Birss LJ noted that the "stance" of the court was always that it has a duty to restrict expert evidence to that reasonably necessary to decide the case. The fact a party requires expert evidence to advance its case does not necessarily justify separate experts. The expert's overriding duty to help the court means that experts are required to, and do, express views on matters which the party calling them would rather were put in a different way or not put at all. That is why the duty is an overriding one. It is not a justification for separate experts.
Birss LJ noted that the power to order a single joint expert "will more usually" be capable of being exercised when it appears to the court that "the issue falls squarely within a substantially established area of knowledge and where it is not necessary for the court to sample a range of opinion or where the issue is uncontroversial". That said, single joint expert evidence is not confined to uncontroversial matters.
The judge also accepted that proportionality, which is one aspect of the overriding objective and governing principles, is not the only consideration. The fact that the value of the case means that the cost of separate evidence would not be disproportionate to what is at stake does not on its own rule out a direction for a single joint expert. The just disposal of the case is also a vital consideration.
When it comes to the use of the SJE, the judge agreed that they tend to be used in smaller claims, with the use of the SJE in "heavy and complex cases" being more limited, although that was not to say that the scope for using the SJE was necessarily more limited in those cases. Indeed, in the case here, one reason for the use of the SJE was the potential for a "multiplicity of economic models and sets of parameters".
This article is based on recent summaries from the Fenwick Elliott Dispatch, a monthly newsletter which highlights some of the most important legal developments during the last month, relating to the building, engineering and energy sectors. You can find further details here: https://www.fenwickelliott.com/research-insight/newsletters/dispatch
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.