Expert Witness in UK Law

It is always desirable that an expert should have no actual or apparent interest in the outcome of the proceedings in which he gives evidence, but such disinterest is not automatically a precondition to the admissibility of his evidence. In considering that question the Judge will have to weigh the alternative choices open if the expert's evidence is excluded, having regard to the overriding objective of the Civil Procedure Rules.

It needs to be emphasised that, if a party needs the permission of the court to rely on expert witness A in place of expert witness B, the court has the power to give permission on condition that A's report is disclosed to the other party or parties, and that such a condition will usually be imposed.

There are various aspects of such evidence in respect of which the Trial Judge can get the "feeling" of a case in a way in which an Appellate Court, reading the transcript, cannot. Sometimes expert witnesses display signs of partisanship in a witness box or lack of objectivity. This may or may not be obvious from the transcript, yet it may be quite plain to the Trial Judge.

An expert's opinion is admissible to furnish the Court with scientific information which is likely to be outside the experience and knowledge of a Judge or jury. An expert's opinion is admissible to furnish the Court with scientific information which is likely to be outside the experience and knowledge of a Judge or jury. An expert's opinion is admissible to furnish the Court with scientific information which is likely to be outside the experience and knowledge of a Judge or jury.

While some degree of consultation between experts and legal advisers is entirely proper, it is necessary that 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. To the extent that it is not, the evidence is likely to be not only incorrect but self defeating.

But that seems to me to fall squarely within the traditional witness immunity. The alleged cause of action was a statement of the evidence which the witness proposed to give to the court. A witness owes no duty of care to anyone in respect of the evidence he gives to the court.

I certainly accept that there may be perfectly good reasons for a party to wish to instruct a second expert. That means that it will often, perhaps normally, be proper to allow a party the option, at his own expense, of seeking a second opinion. It would not usually be right simply to deny him permission to rely on expert B and thus force him to rely on expert A, in whom he has, for whatever reason, lost confidence.