That discipline is not decorative. It is the difference between expert evidence that assists the court and expert evidence that merely supports a party’s case.
The language of Part 35 is familiar to most litigators and expert witnesses in England and Wales. Experts owe a duty to the court. That duty overrides any obligation to the party instructing or paying them. Expert evidence must be limited to what is reasonably required to resolve the proceedings. Reports must comply with the requirements of Practice Direction 35. Experts must provide independent opinions, consider material facts, identify the limits of their expertise and avoid acting as advocates and none of this should be controversial.
Yet in practice, Part 35 compliance still causes problems because too many reports treat it as a final-page declaration rather than a working method.
The problem with formulaic compliance. Most expert reports now contain the required statements. The expert confirms that they understand their duty to the court. They confirm that they have complied with that duty. They verify the report with a statement of truth. That matters, but is it enough? A compliant report is not made compliant by adding the correct wording at the end. The body of the report must show the same discipline. If the reasoning is selective, the analysis incomplete or the expert’s opinion unsupported, the formal declaration does little to save it. This is where medico-legal reports often fall short.
An expert may record the claimant’s account in detail but give insufficient attention to contradictory medical records. Another may accept instructions too narrowly and fail to engage with alternative explanations. A report may state a conclusion on causation without explaining the reasoning that connects the accident to the alleged injury. The court does not need an expert simply to repeat what the claimant says. Nor does it need an expert to echo the suspicions of a defendant. It needs independent analysis. Part 35 compliance should be visible in the reasoning, not just in the wording.
Independence is the core issue. The expert’s duty to the court is the centre of the entire Part 35 regime. It is also the part most easily diluted in practice. Instructing parties naturally want helpful evidence. Claimant solicitors want reports that support causation and ongoing loss. Defendants want scrutiny of exaggeration, inconsistency and pre-existing conditions. Those pressures are part of litigation. The expert’s role is to resist them. Independence does not mean neutrality in the sense of having no opinion. Experts are instructed precisely because they are expected to give opinions. The issue is whether those opinions are genuinely their own, properly reasoned and based on all material facts.
A strong expert report can support a claimant. A strong expert report can support a defendant. The problem arises when the report appears written to satisfy the expectations of the instructing party rather than the needs of the court. That is not a minor defect. It goes to reliability. An expert who overlooks evidence that weakens their conclusion is not assisting the court. An expert who strays beyond their field is not assisting the court. An expert who fails to acknowledge uncertainty is not assisting the court. Part 35 compliance requires intellectual honesty.
The facts that do not help.
One of the most important features of Practice Direction 35 is the expectation that experts consider all material facts, including those which may detract from their opinions. That requirement is not always reflected in medico-legal practice.
In personal injury claims, the facts that do not help may include prior symptoms, delayed attendance, inconsistent histories, alternative causes, degenerative findings, employment records or evidence of higher function than the claimant reports. In clinical negligence claims, they may include uncertain causation, recognised complications, conflicting factual accounts or limits in the available records.
A report that ignores these issues may look persuasive on first reading. It may even help settlement discussions in the short term. But it is vulnerable. The more difficult facts are often the ones that most need analysis however, a credible expert does not hide them. They confront them. They explain whether those facts change the opinion and, if not, why not. That is what gives the report weight.
There is a commercial temptation to produce reports that are smooth, simple and supportive. The better report is often less tidy. It may contain qualifications. It may identify uncertainty. It may explain that a conclusion is possible rather than probable, or that further evidence is needed before a firm view can be reached. That is not weakness but compliance.
When the expert becomes an advocate. The line between expert evidence and advocacy can become blurred. It happens when an expert uses language that sounds forensic rather than clinical. It happens when the report argues the case instead of analysing the evidence. It happens when the expert selects favourable facts, dismisses contrary facts too quickly or expresses opinions on issues properly reserved for the court.
In medico-legal work, this risk is particularly acute because experts are often asked questions that sit close to credibility. Is the claimant exaggerating? Was the injury caused by the accident? Could the claimant have returned to work earlier? Are the reported restrictions plausible? These are legitimate areas for expert comment, but they require care. An expert can say that symptoms are inconsistent with the records. They can say that the reported recovery period is longer than expected. They can say that the clinical presentation does not support the level of disability alleged. They can explain that causation is not established on the available medical evidence.
What they should not do is make unsupported findings of dishonesty.
Fraud is not a diagnosis. Dishonesty is usually a matter for the court.
The expert’s role is to provide the medical analysis that helps the court reach its own conclusion. When experts forget that boundary, they weaken their own evidence.
Compliance starts before the report is written.
Part 35 problems do not begin at the signature page. They often begin at instruction.
Poor instructions produce poor reports, if the expert is not asked the right questions, not given the relevant documents or not told the issues in dispute, the report is likely to suffer. That is not only a problem for the expert. It is a problem for the party seeking to rely on the evidence. The court’s permission for expert evidence is not a blank cheque. The field of expertise and the issues to be addressed matter. So does proportionality. Expert evidence should be used because it is reasonably required, not because it is tactically convenient.
This is particularly important in lower-value injury claims where expert evidence can easily become formulaic. A short report may still need proper reasoning. A fixed-cost report may still need independence. A routine whiplash assessment may still need to engage with medical history, symptom onset, recovery and any inconsistencies in the records.
Compliance is not reserved for high-value litigation. It also applies whenever expert evidence is being prepared for proceedings, written questions and joint discussions are not afterthoughts and part 35 also provides mechanisms for testing and refining expert evidence.
Written questions can be used to clarify a report. They should not become cross-examination by correspondence. Properly used, they help expose gaps, resolve ambiguity and narrow dispute. Poorly used, they add cost and hostility without improving the evidence.
Discussions between experts serve a similar function. Their purpose is not to settle the case. It is to identify agreement, isolate disagreement and explain the reasons for each. A good joint statement can transform litigation because it shows the parties and the court what remains genuinely in issue.
This part of the process matters because expert disagreement is not always as wide as it first appears.
Two experts may agree on diagnosis but disagree on duration. They may agree on injury but disagree on causation and they may agree on prognosis but disagree on the effect of pre-existing symptoms. The joint process should make those distinctions clear.
That is efficient. It is also fair.
The real value of compliance.
The medico-legal system does not need more reports that merely look compliant. It needs reports that are compliant in substance.
That means independence from the start. It means proper engagement with difficult facts. It means clear reasoning. It means acknowledging uncertainty. It means staying within expertise. It means remembering that the report is addressed to the court, not to the party paying the invoice. Part 35 compliance is not a technical hurdle, it is a quality control system. The experts who understand that produce better evidence and solicitors who understand it give better instructions. Courts that enforce it protect the integrity of the litigation process.
The point is simple. Expert evidence is powerful because it claims independence and if that independence becomes cosmetic, the whole system pays the price.
