Expert Evidence: Part 35 of the Civil Procedure Rules

We continue our mini-series focused on quantum expert evidence by building on last week’s Expert vs. Advocate: the difference article. In this second article, we recap the basic principles of Part 35 of the Civil Procedure Rules ("Part 35"), which are binding rules that any expert giving evidence in court proceedings in England & Wales must comply with.

Expert Evidence in Court Proceedings

Expert evidence is used to help the court when the dispute before the court involves technical or specialist matters that are outside of the court's expertise.

An expert's duties to the court are set out in Part 35 and its accompanying practice direction. It is the duty of experts to help the court, and this duty overrides any obligation to the party who is paying the expert.

Any expert providing evidence to the court in England & Wales must comply with Part 35. An expert's report can be rejected by the court if an expert has failed to comply with its duties.

It is generally recommended that any expert providing evidence in other dispute resolution proceedings, such as adjudication, comply with Part 35 so as to give their evidence more credibility and weight.

Non-compliance with Part 35 in this respect could have the effect of turning expert evidence into advocate’s evidence. If you are procuring expert services, then your instructions to the expert should expressly set out whether the expert is required to comply with Part 35.

General Requirement

The expert's evidence should be the independent product of the expert, objective, and unbiased. An expert must not seek to support the claim of the party instructing them.

The expert must consider all material facts, including those that might detract from their opinion, and must make it clear when a particular issue or question falls outside of their expertise. The expert must also expressly state if they are unable to reach a definite opinion on a particular point, for example, if they have insufficient information.

If, after producing their report, the expert's view changes, then the expert must inform all of the parties and the court of this change of view without delay. When experts receive new information, they should be prepared to reconsider and change their minds.

The Expert Report

An expert's report must:

List all literature, documents, or other material that has been relied on in making the report. Any documents referred to must be provided to the opposite party at the same time as the report;

• Contain a statement setting out the substance of all facts and instructions which are material to the opinions expressed in the report and upon which those opinions are based;
• Give details of the expert's qualifications and make clear which of the facts stated in the report are within the expert's own knowledge (and which have been told to the expert by others);
• Contain a summary of the conclusions reached by the expert;
• Where there is a range of opinion on the matters dealt with in the report, summarise the range of opinions and give reasons for the expert's own opinion;
• Contain a statement that the expert understands their duty to the court and has complied with that duty and that the expert is aware of the requirements of Part 35, its practice direction and the Guidance for the Instruction of Experts in Civil Claims 2014
• Be verified by a statement of truth using specified wording.

Guidance for Parties

When instructing an expert, it is important to expressly remind them of their duty to comply with Part 35 and that their report must be independent.

Any instructions provided to the expert are disclosable, which means you might be required to share these with the other parties. So, it is recommended that you don't include any information in the instructions that you would not want the other parties to know about.

Usually, an expert will issue a draft report to the party instructing it for review. The report must be labelled draft until it is final; otherwise, it might be disclosable in court proceedings.

When reviewing an expert report, you can point out any typographical or factual errors to the expert and could ask for further explanation if a particular part of the report is not clear. However, it is important to note that a party can't ask an expert to change their report or to remove sections from their report. The report cannot be influenced at all by the party that is instructing the expert.

Further Reading

Any quantum expert should review the following documents before agreeing to act as an expert:

• CPR Part 35 and its Practice Direction
• RICS Practice Statement: Surveyors acting as expert witnesses
• Civil Justice Council Guidance for the instruction of experts in civil claims
• The relevant Court Guide such as the TCC or the Commercial Court.

Final reflections

An expert's credibility rests entirely upon their ability to be independent and unbiased. Failure to comply with Part 35 can ultimately result in the expert evidence being disregarded by the court and can cause long-term reputational damage for an expert. As such, it is important that experts are familiar with the requirements of Part 35 before accepting any instructions.

In next week’s article, we will build on this article by moving from the ‘macro expert picture’ to the 'micro expert picture’ and cover guidance for quantity surveyors acting as expert witnesses.

Keep an eye out for that, and, in the meantime, enjoy the rest of your week!

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