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Caution! Is your expert witness too close for comfort?


A recent UK ruling will serve as a word of warning to parties to litigation to exercise caution when instructing expert witnesses holding any connection or familiarity with the parties to proceedings.

In EXP v Barker ( EWCA Civ 63 the UK Court of Appeal ruled that an expert witness who had worked and had co-authored research papers with the appellant in the past held too close a connection to him to fulfil his duty of providing independent and objective evidence.   

A consultant doctor appealed against a first instance ruling, where the trial judge had found that the defendant had negligently failed to identify and report the claimant’s aneurysm. The trial judge had called into question the objectivity of the defendant’s expert’s evidence and refused to place any significant weight on it due to the fact that the defendant had failed to disclose that he had previously held a close working relationship with the expert. Both the expert and the defendant had submitted CVs to the court yet any collegiate connection between them had been notably excluded. The trial judge had stated that the court could not satisfy itself of the independence and objectivity of an expert witness in a situation where a connection had existed and where the defendant had attempted to avoid the exposure of that connection. 

On appeal, the court held that the trial judge was “fully entitled” to take the view that the weight accorded to the expert witness’ evidence was significantly diminished due to his relationship with the appellant. The court went so far as noting that had the trial judge decided to exclude the expert’s evidence entirely it would have been a “proper decision”. 

This decision falls perfectly in line with the direction that the law on expert evidence is currently heading here in Ireland.  The recently published Law Reform Commission’s (“LRC”) Report on Consolidation and Reform of Aspects of the Law of Evidence makes recommendations that mirror the UK court’s judgment. The LRC Report, which was launched on 18 January of this year, makes 87 recommendations for reform, including providing for the four main duties of an expert witness to be set out in legislation, comprising of an overriding duty to provide truthful, impartial evidence. The four duties owed by the expert to the instructing party are identified as:- 

  1. Duty to exercise due care, skill and diligence
  2. Duty to avoid and disclose any conflict of interest
  3. Duty to limit contentious issues
  4. Duty to sign expert’s declaration

The LRC’s recommendatory paper, combined with this recent decision serve to emphasise, once again, the importance of independence and objectivity in expert evidence. It is also a timely reminder to ensure that if some sort of a relationship or connection cannot be avoided between the party and the expert instructed that this should be disclosed in a forthright manner. 

Contributed by: Adele Hall