THE EXPERT AS ADVOCATE AND PROVIDING “CRITICAL COMMENTARY”: IMPORTANT POINTS ON THE ROLE OF THE EXPERT WITNESS TO TAKE AWAY
There are some interesting comments on experts in the judgment of Matthew Gullick (sitting as a High Court Judge) in Pepe’s Piri Piri Ltd & Anor v Junaid & Ors  EWHC 2097.
“It is not part of the duty of an expert to advance the case of the party instructing them, whether by advancing arguments of fact or law which are outside their expertise or by seeking to present that party’s case in a favourable light. An expert witness should present evidence which is uninfluenced by the pressures of litigation and contains independent assistance by way of objective opinion.“
The claimant sought damages alleging unlawful interference with the claimant’s business which led to the closing down of the fast food shop in Northampton. Expert evidence was used to quantify the losses.
THE JUDGE’S COMMENTS ON THE EXPERT EVIDENCE
During his cross-examination of Mr Cohen and in his closing submissions, Mr Jones QC criticised Mr Cohen’s approach, contending that it was more akin to that of an advocate for the Defendants rather than that of an expert appointed under Part 35 of the Civil Procedure Rules (CPR). Mr Jones QC pointed to a number of what he said were unsatisfactory features in Mr Cohen’s written and oral evidence. These included that Mr Cohen’s report introduced matters outside his expertise, including general criticisms of the Claimants such as whether the Claimants ought to have issued proceedings against the guarantor of the Franchise Agreement or against Mr Qureshi. Mr Cohen opined at paragraph 3.5 of his report that the failure to issue such proceedings was “very strange”. I agree with Mr Jones QC that Mr Cohen’s report was, in significant part, more of a critical commentary on the Claimants’ conduct of the litigation than an assessment of their claimed losses.
In his oral evidence, Mr Cohen said in response to Mr Jones QC that although his ultimate duty was to the court, where he was instructed by a particular party then he would do the best that he could to present that party’s case in the most favourable light. I do not regard Mr Cohen’s approach, thus explained, as being consistent with the duties of an expert under CPR Part 35. It is not part of the duty of an expert to advance the case of the party instructing them, whether by advancing arguments of fact or law which are outside their expertise or by seeking to present that party’s case in a favourable light. An expert witness should present evidence which is uninfluenced by the pressures of litigation and contains independent assistance by way of objective opinion. Mr Cohen’s understanding of his role as being to present the case of the party instructing him in the most favourable light was, in my judgment, not consistent with the well-established position which is now set out in paragraph 2 of the practice direction to CPR Part 35. I accept Mr Jones QC’s submission that Mr Cohen, insofar as he was critical of the Claimants’ case and of the evidence of Mr Blake, approached the exercise more as an advocate than as an expert complying with the requirements of CPR Part 35. That is not to say, of course, that the Claimants’ case and the evidence of Mr Blake must necessarily be accepted or indeed that the criticisms made by Mr Cohen were necessarily incorrect – indeed, Mr Cohen identified a flaw in Mr Blake’s assessment of the Claimants’ losses which Mr Blake accepted. But, insofar as there is conflict between Mr Cohen and Mr Blake, I am constrained for these reasons to place little weight on the views of Mr Cohen.
Mr Blake, on the other hand, was a witness whose evidence did not suffer from the flaw to which I have just referred in relation to that of Mr Cohen. However, I did consider some of his evidence on the quantification of the Claimants’ claimed losses to involve a considerable degree of speculation. Mr Blake himself recognised in his report that it was not possible on the available evidence to quantify with precision certain aspects of the Claimants’ claimed losses. Moreover, he accepted after his discussion with Mr Cohen that he had overvalued the Claimants’ losses in some respects. He therefore produced a supplementary report which revised downwards his quantification of those claimed losses. Whilst I am able to place greater weight on his evidence than that of Mr Cohen, I do remind myself that ultimately the decision as to the extent of any losses is a matter for me and not one on which the expert evidence adduced by either side, although of assistance, is determinative.