Cresswell J. in a pre- CPR case set out what could be expected of expert witnesses.
The Duties and Responsibilities of Expert Witnesses
The duties and responsibilities of expert witnesses in civil cases include the following:
- Expert evidence presented to the court should be, and should be seen to be, the independent product of the expert uninfluenced as to form or content by the exigencies of litigation..:.
- An expert witness should provide independent assistance to the court by way of objective, unbiased opinion in relation to matters within his expertise… An expert witness in the High Court should never assume the role of an advocate.
- An expert witness should state the facts or assumptions upon which his opinion is based. He should not omit to consider material facts which could detract from his concluded opinion…
- An expert witness should make it clear when a particular question or issue falls outside his expertise.
- If an expert’s opinion is not properly researched because he considers that insufficient data is available, then this must be stated with an indication that the opinion is no more than a provisional one… In cases where an expert witness, who has prepared a report, could not assert that the report contained the truth, the whole truth and nothing but the truth without some qualification, that qualification should be stated in the report…
- If, after exchange of reports, an expert witness changes his view on a material matter having read the other side’s expert’s report or for any other reason, such change of view should be communicated (through legal representatives) to the other side without delay and when appropriate to the court.
- Where expert evidence refers to photographs, plans, calculations, analyses, measurements, survey reports or other similar documents, these must be provided to the opposite party at the same time as the exchange of reports…
Edited for ease of reading. The rules governing expert evidence are not set out in CPR 35, PD 35 and the Guidance.