Recent law reports have included a surprising number of cases in which the judge has taken 'airtime' to criticise the expert witness. Judicial fulminations have concentrated much of the heat on questions of conflict of interest and independence.
But the duties of expert witnesses are set out explicitly in guidelines issued both by the court and by the Academy of Experts. The expert's duty is to the court and this overrides any other duties the expert may have to those instructing him or her. The expert must not assume the role of advocate for the instructing party, but must be independent and objective. The expert must not have a financial interest in the outcome of the case. The expert signs a declaration acknowledging these duties.
In one case, an expert was appointed to give evidence on behalf of a barrister sued for negligence, but the court could not accept his testimony. The problem was that the expert was another barrister in the defendant's own chambers – a friend as well as a colleague of the defendant – and the judge ruled that this gave rise to a possible conflict of interest that might affect his independence. It is not the specific facts of the case that are concerning, or the judge's decision. What is difficult to understand is why a case such as this should be reported, allowing lovers of precedent to seize upon the judge's remarks and try to apply them in other situations.
The judicial concern about such conflicts does not appear to extend to barristers when they appear as barristers. It is accepted that barristers, even in the same chambers and sharing the same clerks and fax machine, can be on opposing sides in a case. Quite why the judiciary is concerned about conflicts for experts, who are more able to establish effective Chinese walls, is unclear.
The much-publicised decision in the Prince Jefri case also concerned conflict of interest and Chinese walls. Here, certain forensic accountants who had been working with Prince Jefri on one case accepted instructions by another party against the prince shortly after the first case had settled. Financial information relating to the first case may also have been pertinent to the second. As a result, the judge in the second case made various remarks on when Chinese walls can and cannot be effective. Lurking within the judgment, but not expressed as part of it, was the implication that if one part of an international organisation has some involvement with a party, an expert witness from another part of that organisation might have a conflict of interest and/or be in a position to gain information that would otherwise be privileged and presumably then pass it on to his colleagues in the other part of the organisation.
Any suggestion that information known within one part of a large organisation will inevitably become known elsewhere in that organisation should be treated with scepticism. The reality is very different in organisations that have many separate departments and operate in many separate offices and countries. Generally, there is no difficulty in establishing a Chinese wall to prevent any flow of potentially privileged or confidential information.
It is sometimes suggested that if a firm provides other services to the instructing party, one of its members cannot provide independent evidence. Lurking behind this suggestion is a presumption of bias in the expert. In an adversarial system where the expert is paid for his time by the party instructing him, there will always be the possibility of bias. The court has dealt with this by requiring the expert to sign a declaration in his report acknowledging his duty to the court above all else. Any expert showing bias can expect to be the subject of adverse criticism by the judge.
Concerns about the difficulties faced by expert witnesses appear exaggerated. The expert's duties are clearly defined by the court and most firms have procedures in place that will enable them to avoid serious conflicts in relation to existing clients. Providing the expert himself is sufficiently remote from the existing relationship maintains adequate Chinese walls and abides by the court guidelines, and so conflicts of interest and independence should not be a problem for anyone.