When the Evidence Changes: A Care Expert’s Duty to the Court

In personal injury and clinical negligence litigation, expert witnesses are often asked to assess complex injuries and long-term care needs. We’re not there to prove or disprove a claim and, in our role, we assist the court with independent, impartial and clinically evidenced opinions.

But what happens when new evidence is presented that changes the direction of a case?

In 2021, I was instructed as a care expert in a personal injury claim that ultimately resulted in the judge making a ruling of ‘fundamental dishonesty’. The case — O’Connell v The Ministry of Defence [2025] EWHC 2301 (KB) — was a reminder of how, even when the evidence changes, the duty of the expert does not. That duty remains, always, to the court.

The initial findings of O’Connell v The Ministry of Defence

As the instructed care expert, my role was to assess the claimant’s functional needs arising from her alleged injury. This involved visiting the claimant at her home, assessing her activities of daily living, and recommending any required assistance, aids, equipment, and services that would maximise independence.

After suffering a fracture in her left collarbone, the claimant had reported significant limitations in range of movement in her left arm, as well as ongoing pain and hypersensitivity around the shoulder. As a result, she reported that she needed assistance with personal hygiene, dressing and meal preparation. She also stated that she could no longer drive a manual vehicle and had therefore purchased an automatic.

When I assessed the claimant, she presented as credible. Pain is subjective, and functional limitations can vary between individuals. I had no reason to doubt what I was being told, and I was not there to interrogate or challenge — my role was to assess and evaluate based on the information available at the time.

When surveillance evidence contradicts a care expert report

Shortly after my assessment, I was sent surveillance evidence that had been gathered during litigation.

The footage demonstrated that the claimant had a much greater degree of movement in the injured arm than reported. It showed the claimant driving a manual vehicle, as well as undertaking physically demanding tasks that would not have been possible if she was suffering from the level of disability she described.

The claimant had also reported severe pain and hypersensitivity around the shoulder, but was wearing an elbow immobilising brace. She told me that this reduced her pain. However, such braces aren’t typically designed to manage collarbone or shoulder injuries and, in my clinical opinion, the weight of the brace would have been more likely to increase shoulder discomfort rather than relieve it.

When new material evidence becomes available, a care expert has a professional obligation to review their conclusions.

Having considered the surveillance footage, I revised my care report and recommendations to reflect the functional capacity demonstrated by the claimant. I commented that, in my opinion, there was some exaggeration regarding the level of disability reported by the claimant. I also noted that deciding whether this was conscious or subconscious was a matter for the court.

It later became clear that other experts involved in the case had found similar inconsistencies, and fundamental dishonesty concerns were raised by the defendant team.

The duty of an expert witness under the Civil Procedure Rules

It’s important to note that, under the Civil Procedure Rules, an expert witness’s primary duty is to the court, not to any instructing party.

That duty requires us to:

• ›Provide independent and impartial opinion
• ›Consider all material facts in the claim
• ›Come to conclusions based on clinical evidence
• ›Revise our opinion if new and relevant evidence emerges

An expert report must be objective and defensible, and therefore it should not be a fixed position that cannot change. If fresh evidence contradicts earlier conclusions, maintaining an outdated opinion risks undermining the credibility of both the report and the case.

In this particular case, in his judgement, the judge commented that one of the experts for the claimant should have provided their opinion on veracity after viewing the surveillance footage, to assist the court. They had done so in the initial reports, but omitted to do so in their subsequent reports.

The court ultimately found that the claimant had been fundamentally dishonest, meaning that the dishonesty went to the root of the claim and the claim was dismissed.

Why updated an expert witness report is not a weakness

There can sometimes be a misconception that revising an expert report is a sign of uncertainty or weakness. But in my view, the opposite is true.

Updating an opinion in light of new evidence demonstrates:

• ›Professional integrity
• ›Clinical reasoning
• ›Compliance with the Civil Procedure Rules
• ›Commitment to assisting the court

Throughout a case, expert witnesses must be prepared to reconsider conclusions when new information emerges. Far from being a flaw in an expert, it is an essential part of independent expert practice.

Courts expect transparency, and they expect experts to engage with all available evidence. Failing to do so can expose a report to criticism and potentially weaken a case.

Why clinical experience matters in care expert witness evidence

I have over 20 years’ experience as a Registered Nurse/Advanced Nurse Practitioner, including senior roles in medical, surgical, emergency and major trauma services, and latterly general practice. I was involved in the development of the Leeds Major Trauma Centre and have extensive experience managing patients with orthopaedic injuries similar to those sustained in this case.

A clinical background that is relevant to the case is important in care expert witness work.

In this particular case, it allowed me to understand:

• ›Expected recovery trajectories
• ›Typical functional outcomes
• ›The relationship between reported pain and objective findings
• ›When reported limitations fall outside expected norms

Pain is always subjective (and every individual’s recovery is unique), but experience means we can recognise when the level of reported disability appears disproportionate to the injury sustained.

In litigation, that understanding must be applied carefully and objectively.

What solicitors should know about Fundamental Dishonesty and expert evidence

For those instructing care expert witnesses in personal injury or clinical negligence cases, O’Connell v The Ministry of Defence highlights several important considerations:

• ›Ensure all relevant evidence — including surveillance — is shared promptly with experts
• ›Instruct experts who understand their duty to the court, and adhere to it
• ›Recognise that independent opinion strengthens credibility, even if updates or revisions are required
• ›Value clinical experience when assessing complex or high-value care claims

Independent expert evidence protects not only the integrity of the case but also the credibility of the legal team relying upon it.

Tessa Gough Associates — Care at every level

At Tessa Gough Associates, our expert witnesses are trained to provide independent and impartial care expert reports for both claimant and defendant solicitors. Our role is not to advocate for any side. It is to assist the court with clear, objective, and defensible opinions.

When the evidence changes, the duty remains the same.