CPR Part 35 is Part 35 of the Civil Procedure Rules, the framework that governs civil litigation in England and Wales. It sets out the rules for expert evidence: who can give it, what form it must take, and what obligations the expert owes to the court.
If you have ever been involved in a personal injury claim, whether as a solicitor, insurer or claimant, you will have come across the term CPR Part 35. It appears on every medico-legal report, every letter of instruction, and every court bundle. Yet for many people, what it actually means and why it carries such weight remains surprisingly unclear.
What is CPR Part 35?
The central principle is this: a medical expert's duty is to the court, not to the party that instructed them. This is not a technicality. It is the foundation on which the entire system of independent expert evidence rests. A doctor who writes a report favourable to the instructing solicitor rather than giving an honest clinical opinion is not just professionally at risk, their report can be struck out entirely, leaving the claim without medical evidence.
CPR Part 35 also requires that every expert report contains a declaration confirming the expert understands and has complied with their duty to the court. Without that declaration, the report does not comply with CPR Part 35, and whether it can be relied on is a matter for the court.
What must a compliant report contain?
A CPR Part 35 compliant medico-legal report must include several specific elements. It must state the expert's qualifications and the basis of their opinion. It must set out the facts and literature the expert has relied on. It must distinguish clearly between what the expert was told by the claimant and what they observed or clinically assessed themselves. It must give a clear prognosis, how long symptoms are likely to last, whether they are permanent, and what treatment has been recommended.
Critically, the report must contain a statement of truth and the Part 35 declaration. Both must be signed by the expert in their own name, not by a medical agency or anyone else.
Reports that are vague, that conflate fact with opinion, or that fail to address causation directly are regularly criticised by courts. Judges are experienced in reading medical evidence. A report that reads as if it was written to support the claim rather than assess it objectively will undermine the case rather than strengthen it.
Why does it matter for RTA and personal injury claims?
In road traffic accident claims, workplace injury claims and clinical negligence cases, the medical report is often the most important document in the entire file. It establishes whether the accident caused the injury, how severe the injury is, how long recovery will take, and what treatment is needed. Compensation is calculated directly from those findings.
If the report does not comply with CPR Part 35, the defendant's solicitors will challenge it. If it is successfully challenged, the court may refuse to admit it as evidence. At that point, the claimant has no expert medical evidence to support their case, and in most personal injury claims, that is fatal to the claim.
This is why instructing a report through a reputable, MedCo-registered Medical Reporting Organisation matters. A good MRO does not just arrange an appointment. It checks that the expert is appropriately qualified and registered with the relevant regulator, and that the report addresses all the required elements.
The difference between a good report and a poor one
In practice, the difference between a CPR Part 35 compliant report and a non-compliant one is not always obvious at first glance. Both may look professional. Both may be written by a doctor. But there are specific things that separate reports that hold up from those that do not.
A strong medico-legal report will clearly identify the mechanism of the accident and link it to the specific injuries described. It will give a detailed clinical examination with objective findings, not just a record of what the claimant reported. It will address the prognosis with specific timeframes rather than vague language like "may improve over time." And it will give a clear opinion on causation: whether, on the balance of probabilities, the accident caused the injuries claimed.
A weak report will be heavy on history and light on clinical examination. It will not engage with causation directly. It may rely excessively on the claimant's account without applying clinical judgment to it. These reports are easy to attack in cross-examination and are routinely criticised in costs proceedings.
Addendum reports and Part 35 questions
Once a medico-legal report has been served, the other party has the right to put written questions to the expert under CPR Part 35.6. These questions must be answered by the expert personally. If the questions raise a genuine dispute about the evidence, the expert may be asked to prepare an addendum report addressing specific points.
This is another area where the quality of the original report matters. A well-written, thorough report will answer most questions before they are asked. A vague or incomplete report invites challenge and generates additional cost and delay for everyone involved.
How MedCo fits alongside CPR Part 35
For soft tissue injury claims by vehicle occupants after road traffic accidents, the first medical report has to be sourced through MedCo. The solicitor searches the MedCo portal and is offered a random shortlist of MedCo-registered MROs or Direct Medical Experts to choose from, a system designed to keep the commissioning of reports independent. An MRO chosen from the shortlist then instructs a MedCo-accredited expert from its own panel. MedCo's rules sit alongside CPR Part 35; they do not replace the expert's duty to the court.
MedCo audits registered MROs against the Ministry of Justice's qualifying criteria, and an MRO that fails an audit can be suspended or removed from the system. MedCo also reviews the quality of accredited experts' reports through peer review.
The bottom line
CPR Part 35 is not bureaucratic box-ticking. It is the legal mechanism that ensures expert medical evidence in civil courts is genuinely independent, genuinely expert, and genuinely useful to the court in deciding cases fairly.
For solicitors, it means choosing your medical reporting partner carefully. A report that fails CPR Part 35 compliance does not just cost money to replace, it costs time, client trust and potentially the claim itself.
For claimants, it means understanding that the quality of your medical evidence matters as much as the strength of your legal case.
Expert Medical arranges CPR Part 35 compliant independent medico-legal reports across a wide range of personal injury claims. Every report is prepared by an expert registered with the GMC, HCPC or GDC, with appropriate specialist qualifications. Every instruction is handled by a dedicated case manager from opening to delivery.
To instruct a report or discuss your requirements, call 0203 8233 222 or visit expertmedical.co.uk/contact.