Civil Procedure Rules: Part 35 Questions for Expert Witnesses

November 12, 2021

James Kinsey

Well-considered Civil Procedure Rule (CPR) Part 35 questions put to medico-legal experts can prove fatal to a claim. Recently, I was instructed late on in a case to advise a claimant who alleged he sustained soft tissues injuries arising from a road traffic accident involving a bus on which he was a passenger. The defendant’s questions put to the claimant’s GP expert led to the claimant’s personal injury claim losing all prospects of success, an allegation that the case had been brought dishonestly, and ultimately the discontinuance of the claim.

At his medico-legal examination, the claimant stated that he was ‘thrown forwards and backwards’ on the bus causing him to suffer soft tissue injuries to his neck, left shoulder and right knee. Unbeknownst to the claimant, the bus contained a CCTV camera. The camera captured how the collision impacted upon the claimant’s body, or as it transpired, not impacted upon the claimant’s body. Contrary to the history provided to the expert, it was clear from the video that the claimant was not thrown forwards and backwards. Secondly, there was no visible sign of significant, if any, neck movement capable of causing a whiplash injury. Thirdly, there was no visual evidence to substantiate how the claimant injured his knee.

Naturally, the defendant asserted that the CCTV evidence demonstrated that the collision did not cause the claimant injury, and further that the video evidence showed the claimant had issued a claim dishonestly for the purpose of financial gain. The defendant then served the CCTV evidence with Part 35 questions to the claimant’s expert. The expert opined that having viewed the video he doubted that the injuries alleged could have been caused by the collision.

After the expert’s response, the claimant was in a perilous position. He no longer possessed medical evidence to establish, on the balance of probabilities, causation of injury. It was agreed that the claim was bound to fail. Worse, the dishonesty allegation was seriously emboldened.

As Part 35 questions can have a significant impact on litigation, it is important that experts have a clear understanding of the legal framework in which they sit. I recently conducted a seminar on behalf of SpecialistInfo on the essentials of medico-legal work for new and established medico-legal experts. Continuing in the same vein, this article considers why a party may ask Part 35 questions, the procedural rules, and what is expected of experts.

Why ask Part 35 questions?

Why ask questions of an expert after a written report has been produced? It is a strategy not devoid of risk. Questions may reveal the questioning party’s case strategy; highlight at a premature stage in the litigation matters which may later form part of cross-examination; and, if put in a perceived hectoring manner entrench the opposing expert’s opinion. Perhaps they are an exercise in futility unless there’s reason to believe putting questions will substantially improve the questioning party’s case.

However, Part 35 questions are an important weapon in the litigation armoury. They can be used to clarify an opposing party’s evidence in circumstances where the expert’s opinion is unclear on key issues such as causation and prognosis. For example, in relation to causation of an orthopaedic injury, the expert may be asked to clarify the causal connection between an accident and ongoing pain in the context of pre-existing constitutional injuries. Secondly, the questions may be put to attempt to change an expert’s opinion or to widen the expert’s frame of reference so that they consider a range of different views. Thirdly, experts may face questions where they have not identified and addressed relevant entries in medical records and/or to fully assess the significance of relevant material within medical records which have been considered. Fourthly, experts may have to answer questions after a failure to comply with the provisions of CPR Practice Direction (PD) 35 para 3.2 concerning the formalities of reports. For example, where an expert has failed to give details of medical literature relied upon or in cases where there is a range of opinions on the matters dealt with and the expert had not summarised a range of opinions or given reasons for those opinions.

The procedural rules

What are the legal rules governing how questions are put to experts? The procedural rules dictate the time when questions may be asked. Questions may be put once only and must be within 28 days of the service of the report (r.35.6(2)). However, the time frame may be longer or shorter depending on court directions.

Questions put within this timeframe must be proportionate. Unfortunately, the concept of proportionality is not defined. In assessing proportionality, it is useful to turn to the concept of proportionality found within the Overriding Objective of r.1.1. Reams of questions are more likely to be justified in more complex, important and valuable cases which in Personal Injury litigation usually means cases involving more significant life-changing injuries.

Even in cases involving complex brain injuries and multiple experts, the court may take a dim view of voluminous questions. In Mustard v Flower [2019] EWHC 2623 the defendant successfully applied to set aside questions put to the expert on an unprecedented scale. The questions were relevant and addressed acknowledged areas of omission in the defendant’s experts’ reports. However, the questions were found to be wholly disproportionate and unprecedented in length – in some cases the questions and exhibits ran to a whole file of material! Not unsurprisingly the defendant experts contacted the court to raise concerns about the proportionality of the questions. The court found that the omissions in the defendant’s expert evidence could be better addressed by supplementary reports or by the process of joint meetings/statements.

Next, questions must only be put for the purpose of clarification unless the court gives permission, or the other party agrees (r.35.6(2)(c)). Again, and equally unhelpfully, ‘clarification’ is not defined in the rules. The commentary to the rules provides some elucidation: questions ‘should not be used to require an expert to carry out new investigations or tests, to expand significantly on their report, or to conduct a form of cross-examination by post including on the expert’s credibility unless the court gives permission.’

Courts have found that questions that ask an expert to proffer opinion outside the scope of their instructions are likely to go beyond clarification (e.g.: Mutch v Allen [2001] EWCA Civ 76 where an expert was asked if the claimant’s injuries would have been less severe if a seatbelt was worn). Equally invitations to express an opinion conspicuously not previously expressed is also likely to go beyond clarification. For example, in Wilson v Al-Khader [2015] EWHC 4240, the claimant’s expert opined that a claimant in a persistent vegetative state could survive for many years to come. As the expert had deliberately not provided an opinion on the life expectancy of the claimant, the defendant was not permitted to call for the expression of additional opinions by questioning the anticipated life expectancy of a person in a persistent vegetative state, nor to inquire as to the specific anticipated life expectancy of the claimant.

Once questions have been put and answered they are treated as part of the expert’s original report and therefore they have the same status as the main report (r.35.6(3)). This is important to remember as the expert’s duties when drafting their main report apply equally to drafting answers to questions.

What can be expected of experts?

A party may put, and an expert is expected to answer, questions whether they act as a single joint expert or an expert instructed by another party to proceedings. Should experts answer all questions asked?

An expert has a duty to respond to questions properly put. Good practice dictates communicating with an instructing party before answering questions so that the solicitor can assess if the questions are proportionate, put in time, and do no more than seek clarification. If an expert feels questions are improperly put or there is disagreement between the parties as to the propriety of questions, under CPR r.35.14 experts may file to court written requests for directions for the purpose of assisting them in answering questions. If an expert does not answer questions properly put, the court may direct that the instructing party may not rely on their report or that an instructing party cannot recover the fees and expenses of instructing the expert. In these circumstances, it is likely that the non-instructing party would seek an order that the expert must answer questions on the condition the court considers that the questions were appropriately drafted.

Finally, the time for responding is not contained within the rules, but generally set by court directions and is usually in the region of 28 days. After this timeframe, when an expert’s responds to questions by the other side, the expert should copy in both the instructing party and the questioner.


The bus collision case I referred to at the start of the article is a salutary reminder to parties and experts alike of the potential power of Part 35 questions. Interestingly, in that case the defendant was given permission to put a second set of Part 35 questions to the claimant’s expert. Not long after reviewing the CCTV and casting doubt on whether the claimant had sustained injuries, I was surprised to read that he had later produced an addendum report in which he volt-faced for a second time!

Despite his answers to the first set of questions, in the addendum report he opined that the claimant’s medical records were in fact consistent with the treatment and history as provided to him and referred the court back to his opinion on causation within his original report. Due to the expert’s inconsistent opinions, the defendant successfully sought permission to ask a second set of questions. In the second set of questions the defendant outlined entries in the claimant’s medical records that were plainly inconsistent with the expert’s opinion in his addendum report which he had either overlooked or poorly considered.

The second set of Part 35 answers concluded as did the first. The claimant’s expert doubted that the claimant sustained injury in the road traffic accident. Unsurprisingly, the case was speedily discontinued!

This article was originally published in Medico Legal Magazine – Digital Issue 18.