In this article, Ann-Marie Christie, General Counsel at MAPS, examines recent case law highlighting an expert’s duty to clearly communicate and explain any change of opinion during litigation. Using O’Connell v Ministry of Defence [2025] as a case study, the piece reinforces the importance of transparency, timeliness and compliance with CPR Part 35 and the Guidance for the Instruction of Experts in Civil Claims.
This is a short but important article for experts carrying out medico-legal work when they are considering changing their opinion. We consider the case of O’Connell v. The Ministry of Defence [2025] here.
The case
The Claimant was a serving soldier who was injured whilst taking horse-riding lessons as part of her military training. She suffered an injury to her arm, which resulted in her being discharged from the Army. She failed in her personal injury claim, with the judge making a finding that she was fundamentally dishonest. Her dishonesty was supported by her own social media account, video surveillance evidence and the descriptions she gave to the medical experts instructed in her case.
Evidence was obtained from experts in orthopaedics, psychiatry and pain management. The Defendant’s orthopaedic expert drew attention to the fact that the objective clinical findings did not, in his opinion, support the Claimant’s presentation. He commented that the Claimant’s medical records did not support the history given. There was no reference to muscle wasting, which did not correlate with the muscle wasting he had observed some two years previously. This suggested that the Claimant had been using her left arm during the intervening period. There were also no entries of hypersensitivity within the records, which you would expect to see.
The Defendant’s pain expert took the view that the surveillance evidence confirmed the original opinion he had expressed back in 2019, namely that the Claimant appeared to be functioning completely normally, which caused him to doubt her reporting history. He accepted that the issue of veracity was ultimately one for the court to determine, but he properly offered his opinion to assist the court on that issue.
The Claimant’s pain expert had originally opined that she was suffering from CRPS but later changed his opinion, in his second report, in light of the video surveillance evidence. His revised opinion was still broadly supportive, but he no longer considered that she met the diagnostic criteria for CRPS.
In offering his revised opinion, he did not include sections under the same headings as those in his first report, namely ‘Issues of veracity’ and ‘Malingering/symptom magnification/exaggeration’. He also did not make any explicit comment on the issue of veracity, other than to state that it was a matter for the court to consider.
At paragraph 129 of his judgment, the judge commented:
129. Having read his reports and having heard him give his oral evidence, I have come to the conclusion that [the expert] did not, in his second report, comment on his earlier opinion about the Claimant’s honesty and veracity because he was no longer of the views he had expressed there. I appreciate that I have the benefit of hindsight. I have heard all the evidence in the case, some of which was not available to [the expert]. I further appreciate that [the expert] might point to his silence in his second report on the subject of the Claimant’s honesty and consistency as something from which the necessary inferences could be drawn. I am nonetheless of the view that, having made the remarks he made in his first report, it was part of his duty as an expert positively to make clear that he no longer held those views. Had he done so, all parties, including the Claimant herself, would have benefited from that clarity.
If, at any time, an expert wishes to revise or change an opinion that is no longer consistent with the opinion expressed in an earlier report, the expert has a duty to say so.
In the case of Guntripp v. Cheney Coaches Ltd [2012], that is exactly what the Judge said:
“If at any time the expert can no longer support the case of the person who instructed him, it is his duty to say so. Indeed, if the expert forms that view it is far better that he says so sooner rather than later before the litigation costs escalate.”
If an expert has changed their original opinion, two actions are required:
- The change of opinion must be communicated to the lawyers and the parties without delay; and
- The change of opinion must be explained to the instructing lawyers and party, who are entitled to understand the process that has resulted in the change, particularly where that change is to the detriment of that party’s case.
This is clearly set out in the Guidance for the Instruction of Experts in Civil Claims – “The Guidance”– published by the Civil Justice Council and referred to in Practice Direction 35 – here (see paragraphs 14 and 64 – 66 below).
Experts should inform those instructing them without delay of any change in their opinions on any material matter and the reasons for this.
64. It may become necessary for experts to amend their reports:
a. as a result of an exchange of questions and answers;
b. following agreements reached at meetings between experts; or
c. where further evidence or documentation is disclosed.
65. Experts should not be asked to amend, expand or alter any parts of reports in a manner which distorts their true opinion, but may be invited to do so to ensure accuracy, clarity, internal consistency, completeness and relevance to the issues. Although experts should generally follow the recommendations of solicitors with regard to the form of reports, they should form their own independent views on the opinions and contents of their reports and not include any suggestions that do not accord with their views.
66. Where experts change their opinion following a meeting of experts, a signed and dated note to that effect is generally sufficient. Where experts significantly alter their opinion, as a result of new evidence or for any other reason, they must inform those who instruct them and amend their reports explaining the reasons. Those instructing experts should inform other parties as soon as possible of any change of opinion.
Further commentary is provided by the EWI. They state that, as an expert, when new evidence is presented, you must be prepared to consider it whilst maintaining impartiality and independence, and remember that your overriding duty is to the court, not the instructing party.
If you are presented with complex further evidence, do not be afraid to ask the court for time to consider it fully before providing a response. The EWI is working on a new guide to support members on changing their opinion, but in the meantime, members can find further information and guidance on the EWI website.
Learning Points
- Review CPR Part 35 and the Guidance as a useful refresher. It is always helpful to remind yourself of the requirements rather than relying on memory from previous training.
- Does your report comply with CPR Part 35?
- Has your opinion altered in any way from a previous opinion expressed?
- Have you communicated any change of opinion to the lawyers and parties, without delay?
- You must explain any change of opinion. It is not sufficient to remain silent on issues that have caused your opinion to change.