Role expert witnesses English courts


Expert witnesses are an invaluable resource for enhancing the understanding, and assisting with the determination, of complex issues in court proceedings and other dispute resolution procedures. Part 35 of the Civil Procedure Rules (“CPR”) provides detailed rules on the role of expert witnesses in the English Courts and these largely dictate how instructing solicitors may use their experts in this forum.

The Academy of Experts and similar associations also have codes of practice which govern the conduct of experts and the provisions of these codes largely mirror the provisions of the CPR. The codes are not considered here.

Role of an Expert Witness

CPR rule 35.3 provides that an expert witness has an overriding duty to the Court and the role of expert witnesses is largely framed with this in mind.

An expert witness is required to be independent and provide his expertise impartially to assist the judge, rather than the person giving the expert witness his instructions or remuneration. Some of the key rules of the CPR are set out below:

  • Expert evidence is restricted to that reasonably required (CPR rule 35.1) and the Court’s permission is required before calling an expert to give evidence (CPR rule 35.4). If a party fails to obtain permission in advance, the expert’s report may be inadmissible.

  • A written report by the expert is required unless otherwise directed (CPR rule 35.5). An expert’s report must compy with the requirements set out in CPR rule 35.10 (and the practice direction to Part 35) and includes a requirement for experts to set out the basis upon which their report is made. There is a common law requirement that, if an expert changes his mind on a material matter after exchange of reports, that change of view should be communicated to the other party and the Court. Within 28 days of receiving the other side’s expert reports, parties may submit written questions to the experts (CPR rule 35.6).

  • The Court may appoint a single joint expert (CPR rule 35.7) and may require the parties to agree joint instructions. The rationale for this provision is to save costs but, in reality, this is rarely achieved as the parties often need to instruct their own experts to ensure that the single joint expert is properly instructed and, if appropriate, challenged.

  • The Court has wide powers to manage experts by, for example, directing which issues the experts should deal with. The Court also has the power to, and often does, require that the parties’ experts meet to identify agreed issues and those in dispute (CPR rule 35.12). These meetings have the additional advantage of providing a forum in which parties may discuss and negotiate claims.

In addition to the requirements of the CPR, experts may not advise on matters outside the scope of their expertise. As well as such comments being potentially inadmissible, any challenge to an expert witness on this ground may be damaging to the witness’s credibility.

Function of an Expert Witness

The primary function of experts is to provide independent opinion or expertise in a certain area and, in doing so, to assist the judge in reaching his or her decision. However, experts can also be a useful resource for solicitors when handling claims more generally, for example, where instructed at the outset, experts may assist with an evaluation of the merits of a claim or defence. There will, of course, be increased costs involved in instructing experts at an early stage but this may prevent parties incurring substantial costs at a later stage by pursuing flawed claims. It may also lead to better presentation of, and more informed, statements of case.

Experts can also be used effectively during disclosure, to frame requests for further information, to help with inspection of disclosures, and when considering how to examine other lay, and expert, witnesses.

While experts can provide a powerful contribution, the ultimate responsibility for the running of cases remains with the solicitor. The solicitor will have to advise on the selection of experts appropriately to ensure that his or her client obtains the maximum benefit from using an expert witness.