# 3.2 The Civil Procedure Rules

Part 35 of the Civil Procedure Rules (CPR) and the accompanying practice direction enshrine the steps taken to guard experts against the influence of bias and other issues. The reforms introduced several novel measures.

Rule 35.3 puts a duty on experts to help the court on matters within their expertise and makes clear that this overrides any obligation to the party who has paid them or given them instructions. To ensure that the expert understands that duty, the expert must state in their report that they understand that duty. The practice direction echoes this, making clear that an expert ‘should not assume the role of an advocate’.

Reflecting the emphasis on independence and saving costs, courts now have a power under Rule 35.7 to order that expert evidence is given by a single joint expert. A single joint expert acts as the expert witness for both parties rather than just one. This makes it more difficult for them to act as a ‘hired gun’ for one party or the other. It also saves time and money.

Contents of an expert’s report are now quite tightly regulated (see Practice Direction (PD) 3.2), such that an expert must give details of:

- their qualifications
- the literature they have relied upon in forming their opinion
- what facts and instructions are material
- what facts are within their own knowledge
- who was involved in the preparation of the report
- a summary of the range of opinions
- reasons for their opinion (a key point we will return to when considering accountability); and
- a summary of their conclusions.

The rules also permit discussions between experts to narrow the issues, a process sometimes informally referred to as ‘hot-tubbing’ (Rule 35.12 and PD 9.1).

Figure 11 Hot-tubbing

Similar principles are now enshrined in the more recent Criminal Procedure Rules, Part 19 of which deals with expert evidence. These include the duty to the court (19.2), contents of an expert’s report (19.4), hot-tubbing (19.6), and joint experts (19.7).

OpenLearn - Expert evidence and forensic science in the courtroom
Except for third party materials and otherwise, this content is made available under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence, full copyright detail can be found in the acknowledgements section. Please see full copyright statement for details.