TABLE OF CONTENT
Part 35 CPR Explained: Rules for Medical Expert Witnesses in the UK
Did you know that expert evidence is not automatically allowed in every civil claim. Under CPR 35.1, it must be limited to evidence that is reasonably required to resolve the case.
When a medical expert gives evidence in a UK civil claim, their role is not simply to support the person who instructed them. They must help the court to understand the medical facts and give an independent opinion. The rules for this role are mainly set out in Civil Procedure Rule (CPR) Part 35, the accompanying Practice Direction 35 and related guidance. These rules help courts rely on expert evidence that is clear, fair and relevant.
This guide explains CPR Part 35 in simple terms. It looks at what medical experts must do and how their reports should be prepared.
What Is Civil Procedure Rule Part 35?
CPR Part 35 is the part of the Civil Procedure Rules that deals with expert evidence for civil cases in England and Wales. Expert evidence is used when the court needs specialist knowledge to understand an issue. For example, a medical expert may give an opinion about an injury, diagnosis, treatment, prognosis or future care needs.
Under part 35 of the Civil Procedure Rules, the duty of an expert is to the court. This means the expert must give an independent opinion based on their professional knowledge and the evidence available to them.
What Does CPR Part 35 Cover?
CPR Part 35 covers the use of expert evidence in civil proceedings. It sets out important rules about how expert evidence should be prepared and used in the court. For a medical expert, this can include an assessment of a claimant and an opinion about matters within the expert’s medical field. In addition, the court may give directions about:
- Whether expert evidence is allowed
- The issues the expert should address
- The number of experts who may give evidence
- The deadline for serving reports
- Whether experts must meet or discuss their opinions
- Whether a joint statement is required
- The questions that experts should address
Practice Direction 35 gives further guidance on how expert evidence should be prepared and presented.
Rules For Medical Expert Witnesses
Medical experts have several important duties while preparing evidence for court. These duties help protect the reliability and fairness of the evidence. Here the rules for the medical expert witness are mentioned below:
1. Duty To The Court, Not To The Instructing Party
The most important rule is that the duty of an expert is to the court. A solicitor may instruct and pay the expert, but this does not mean the expert should support that party’s case. The expert should give the opinion they genuinely believe is correct based on their knowledge and the available evidence. If the medical evidence does not support part of the claim, the expert should say so.
The expert should not:
- Change an opinion simply to help a party
- Leave out important information that affects their opinion
- Present uncertain evidence as certain
- Act as a lawyer for either side
2. Remain Independent at All Times
Independence is a key part of an expert’s role. A medical expert should reach their own professional opinion. They should not allow the solicitor, claimant or defendant to influence that opinion. An expert should also consider information that may not support the case of the party who instructed them.
In addition to this, Independence does not mean that an expert must be neutral about every medical issue. It means their opinion must be based on evidence and expert judgement rather than pressure from either side.
3. Give Honest and Balanced Opinions
A medical expert should provide an honest opinion. They should explain both the strengths and weaknesses of the medical evidence where relevant. For example, if the medical records support one conclusion but there is evidence pointing in another direction, the expert should address the difference.
Sir Geoffrey Vos, Master of the Rolls, has stressed the importance of expert evidence being reliable and useful to the court. His comments on expert evidence reflect the wider need for experts to provide evidence that assists the court rather than advocates for a party.
4. Stay Within Your Medical Expertise
A medical expert should only give opinions within their area of knowledge and experience. For example, an orthopaedic surgeon may be well placed to comment on a bone or joint injury. They should not automatically give an opinion on a psychological condition unless they have the required expertise. The expert should clearly state when an issue falls outside their expertise. This is important because the court relies on the specialist knowledge of an expert.
5. Be Clear and Easy to Understand
A medical report may contain medical terms, but the overall explanation should be clear. The judge may not have medical training, so experts should explain their views in simple words because it is easy to understand for the jury without any effort.
A good report should:
- Use plain language where possible
- Explain medical terms in simple words
- Separate facts from opinions
- Explain how the expert reached their opinion
- Clearly identify areas of uncertainty
A short and clear explanation is often more useful than a long report filled with complex medical language.
6. Disclose All Relevant Information
An expert should consider all the relevant information provided to them. This may include medical records, scan results, previous reports, treatment records and other evidence relevant to the medical issue.
If new information becomes available and it could change the opinion of the expert then the expert should consider it carefully. The part 35 of the Civil Procedure Rules supports a process where expert evidence is open, clear and properly tested.
7. Cooperation With Other Experts
Experts may be required to discuss the issues in dispute with another expert. The purpose is not to force experts to reach the same conclusion. Instead, the discussion can help to identify the following:
- Matters on which the experts agree
- Matters on which they disagree
- The reasons for their disagreement
8. Compliance With Court Directions
Medical experts must follow relevant court directions. These directions may set deadlines for:
- Preparing reports
- Exchanging reports
- Answering questions
- Meeting another expert
- Preparing a joint statement
Missing a deadline can cause issues for the parties and the court. CPR Part 35 works alongside court orders. An expert should therefore understand both the rules and the specific directions made in the case.
Practical Tips for Medical Expert Witnesses
Medical experts can take several simple steps to improve their reports and reduce the risk of problems.
- Read the instructions carefully: Know exactly what you have been asked to address.
- Check your expertise: Only give opinions within your expert knowledge.
- Review the relevant records: Make sure your opinion is based on the evidence available.
- Stay independent: Do not change your opinion to suit either party.
- Use clear language: Explain medical terms that a non-medical reader easily understands.
- Explain your reasoning: Do not simply state your conclusion. Explain how you reached it.
- Follow court deadlines: Keep track of every direction that applies to your evidence.
Case Study: AZ v Essex County Council
In AZ v Essex County Council (2025), the High Court looked at whether the claimant could rely on psychological expert evidence or not. The claimant planned to obtain a psychological report, but the court said permission was needed under CPR Part 35 before the evidence could be used. The court said it could not decide whether the psychological evidence was needed without seeing the proposed report first. The claimant therefore had to provide the report and explain why the expert evidence was reasonably needed to help the court decide the case.
The case shows that getting a medical or psychological expert report does not mean the court will automatically allow the report. When permission is required, the party must follow the CPR Part 35 rules and show why the expert evidence is relevant and necessary.
It also shows that the court controls the use of expert evidence. The aim is to make sure expert evidence helps resolve the case rather than adding unnecessary material.
Conclusion
Medical expert evidence plays a key role in civil claims in England and Wales. In this process CPR Part 35 sets important rules for how this evidence should be prepared and used in the court. Under the CPR part 35 rules, the duty of an expert is to the court. In addition, a medical expert should remain independent, give an honest opinion, stay within their expertise and explain their reasoning in a clear way. They should also follow court directions and properly consider all the relevant evidence.
The part 35 of the Civil Procedure Rules helps create a clear framework for expert evidence. Following these rules can help the court make decisions based on reliable medical information. At Concise Medico, we make the process of obtaining high-quality medical expert evidence simple and efficient for solicitors.
