However, the role of the expert is not confined to giving evidence in a witness box. They are often called on to give advice on the merits of a client's case, produce a report and/or meet an opposite number to agree items and narrow the issues.
Particularly during these meetings, the expert may change his or her mind. This may not suit a client but the expert has a duty to act as an officer of the court. Therefore, the immunity is extended to the expert's work that is "principally and proximately" related to the court action.
Raiss vs Palmano (2000) was originally about rent levels in Covent Garden, London. Mr Palmano had falsely claimed he was a member of the RICS' arbitration panel and had practised for 19 years in London, gaining extensive experience of open market property transactions in central London. Through his then solicitors, Mr Raiss engaged Mr Palmano as his expert witness.
The job of counsel in cross-examination is to undermine the credibility of the witnesses. Unfortunately for Mr Palmano, the first of his statements was not true. Even more unfortunately, this came out in cross-examination. He also admitted that he had no particular expertise in the field of property in Covent Garden (as opposed to central London) whereas the opposition's expert did possess that specialist knowledge. In addition, Mr Palmano found difficulty answering questions put to him over whether the other party's advisers had been negligent and/or in breach of contract.
Mr Palmano's client described his performance as "a disaster". Mr Raiss's solicitors and counsel advised their client that his counterclaim was unsustainable and he lost the action.
Mr Raiss sued Mr Palmano. The case came before the court where the judge, in examining the evidence, noted that the case was essentially about the claimant's contention that he had chosen the wrong man for the job because Mr Palmano was not as well qualified as he alleged.
The judge said that in respect of Mr Palmano's inability to answer questions in respect of Covent Garden, the immunity should stay. However, when it came to the claimed membership of the RICS arbitration panel he concluded it was a deceitful act and, therefore, the immunity should be lifted.
Both sides appealed against that decision. Mr Raiss argued that nothing should have been excluded; Mr Palmano contended that nothing should have been allowed to stand.
Mr Justice Eady refused to make the distinction between incompetence and deceit, concluding that the decision was wrong.
He noted that the defendant's failures had not necessarily affected the outcome of the case. Mr Justice Eady said that if it had been known that Mr Palmano was not a member of the RICS' arbitration panel he might not have been appointed, but the outcome might well have been the same if another expert had acted instead of him.
Similarly, it was not claimed that Mr Palmano's report was wrong. It was merely that Mr Palmano could not sustain it in the witness box. Mr Justice Eady suggested that, as the law stood, a defendant would lose immunity if he or she had manufactured evidence. He also took the view that Mr Palmano's behaviour, in falsely claiming that he was a member of the RICS arbitration panel, was no different in kind from that of any other expert who exaggerated his or her suitability for a case. He also noted that an expert witness had to be allowed not only to change his or her mind and retain immunity but also to be immune from action over original statements.
The result? Mr Palmano won. However, Mr Raiss was given leave to appeal.
Moral: choose your expert well.
Ann Wright is a partner in quantity surveyors and contracts consultant Wreghitt and Co.