Related Sector: Expert Witness

Mr Justice Cotter’s judgment in Scarcliffe v Bramton Valley Group Ltd [2023] EWHC 1565 (KB) highlights an essential duty that all experts should be aware of – that is, the duty to re-examine their opinion when new evidence is introduced to a case, and to notify (through legal representatives) the parties and the Court of any change in opinion.

"There was a clear and obvious need for Dr [X] to consider the very significant changes in the orthopaedic evidence since he prepared his report.’’


This was a personal injury claim for damages arising out of an accident, which occurred on 22 September 2017 during the claimant’s employment as a tree surgeon. Ten experts were called to give evidence – two of the experts were consultants in pain medicine and two were consultant orthopaedic spine surgeons.

Expert evidence

After the claimant’s pain expert prepared his report and the joint report, the claimant’s orthopaedic expert’s opinion changed significantly – radically revising his view about acceleration of degenerative change. Further, the orthopaedic experts recognised a week before trial that their combined view on several key issues was wrong.

Before the pain medicine experts were due to give evidence, Mr Justice Cotter asked Counsel (by email) to remind the experts about their duty to notify the parties and the Court of any change in opinion (para 291, Muyepa v Home Office [2022] 2648). He sent this pre-emptively, knowing that the claimant’s pain expert had repeatedly relied on the claimant’s orthopaedic expert’s original opinion, which had since been revised.

Mr Justice Cotter received no response in writing. Both pain experts then went on to give oral evidence ‘’without adequately addressing the obviously relevant and important changes in evidence which had occurred since they compiled their reports’’.

Given that the revised joint view of the orthopaedic experts was available to the parties a week before trial (and was referred to in the skeleton arguments) there was ample time for the pain experts to set out any altered opinion. Instead, however, the claimant’s pain expert’s very marked change in opinion only became apparent during cross-examination. The judge commented that ‘’his hastily prepared addendum report’’ which was prepared at his request ‘’was inadequate and failed to address the issue that was obviously going to be put to him when he gave evidence’’. He also stated that this ‘’radically different view…changed the parties’ realistic valuations of the claim’’.

Duty to notify change of expert opinion.

In his judgment, Mr. Justice Cotter set out the sixth of the Ikarian Reefer principles and CPR 35 PD 2.5. This covers the position where an expert has changed his or her evidence arising out of matters that have occurred after they prepared their written report/the joint report. This includes a change of opinion during a trial.

The relevant provisions are:

  • If an expert’s view has changed, he/she should communicate this (through the legal
    representatives who have instructed him/her) to the other side without delay and when appropriate to the court.
  • An expert should not step into a witness box having changed his/her view without having made this plain beforehand. If the change of opinion is properly communicated, it may alter the need for or extent of evidence to be given.

He then went on explain the relevance of these provisions against the backdrop of litigation.

"As with all other litigation the Court expects the parties within personal injury and clinical actions to seek to (and to continue through the lifetime of the Claim to seek to) achieve a consensual resolution of the claim, or issues within the claim. This includes during a trial. A failure to consider, address and communicate a change/development in an expert’s opinion (if the evidence exchanged continues to be relied upon) may mean that necessary discussions (and for potentially) negotiations either do not take place or proceed on a fundamentally incorrect basis.’’


The judgment reiterated how important it is for the Court to "have the benefit of a carefully considered opinion of an expert, which has been shared and considered by all relevant individuals in advance of the expert giving oral evidence”.

Therefore, experts should ensure that their opinion is reviewed in light of any new evidence that emerges before or even during trial. Any change in opinion should be communicated (through legal representatives) to all parties and the Court in advance of giving evidence in court.

As Mr. Justice Cotter rightly states:

"put simply this late evidence devoid of any adequate analysis should not have been placed before the Court in this fashion and it represented an elephant trap for an unwary Judge.”

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  • Richard

    17 Sep 2023 23:09


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