by W H Rees
The correspondence column of Estates Gazette has recently included numerous references to the position of the expert witness. It is of interest in that connection to consider the opinion of a number of judges.
First, Garland J in the University of Warwick v Sir Robert McAlpine & Sons Ltd [8] NPC 67:
“The nature of the expert evidence in this action and the manner of its introduction prompts me to make some general observations which I hope may in the future assist in the saving of time and costs and also lead to a more precise definition of issues particularly where experts from a number of different but overlapping disciplines are involved.
“First, the role of the expert. It appeared to me that some (but by no means all) of the experts in this case tended to enter into the arena in order to advocate their client’s case. This led to cross-examination on the basis: ‘You have assembled evidence and advanced explanations which you consider most likely to assist your client’s case’.
“It is much to be regretted that this had to be so. In their closing speeches counsel felt it necessary to challenge not only the reliability but also the credibility of experts with unadorned attacks on their veracity. This simply should not happen where the court is called upon to decide complex scientific or technical issues.
“To a large extent this excessively adversarial approach to expert evidence could have been avoided if experts who had at various times expressed contrary or inconsistent views had dealt with this in their reports giving any necessary explanations.
“Similarly, where experts alter their views at a late stage or introduce a wholly new theory or interpretation, the new approach should be reduced to writing and furnished to the other parties at the earliest possible opportunity so that all the relevant experts can give the matter due consideration and, in a proper case, meet in order to define what is common ground and where they differ.
“It is in my view salutary to recall the observations of Lord Wilberforce in Whitehouse v Jordan [1] 1 WLR 246 at p 256:
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.”
Second comes the opinion of Cazalet J, in In re J (A Minor), reported in The Times of July 31 1990:
“His Lordship said that expert witnesses were in a privileged position in that they were permitted to give an opinion in evidence. Such experts had to express only genuinely held opinions which were not biased in favour of one party.
“Opinions could differ but such differences were usually within a legitimate area of disagreement.
“An expert witness should not mislead by omission. A report should provide a straightforward not misleading opinion, be objective, should not omit factors which did not support the opinion and should have been researched properly.
“If the expert considered that the data available were insufficient, then it had to be indicated to the court that the opinion was only provisional.
“An expert witness should avoid providing a report which sought to promote a particular case as that would be an abuse of the expert’s proper function and would render the report an argument not an opinion.
“A misleading opinion would cause costs to be increased because competing evidence would have to be called. In all cases, costs could be reduced if the expert witnesses on each side could discuss together their reports in advance of the hearing.”
Third, the difference between the function of the advocate on the one hand and the expert witness on the other was put succinctly by David Widdicombe QC, sitting as deputy judge in connection with a planning matter [9] JPL 423:
“While there is no rule against someone combining the role of advocate and expert witness at an inquiry it is, generally speaking, an undesirable practice. That is why local planning authorities are not represented at inquiries by their planning officers. An expert witness should be trying to give his true and unbiased professional opinion to assist the inspector. An advocate is trying to argue the best case he can for his client. Someone who combines these conflicting roles must not be surprised if an inspector or a court approaches his evidence with a degree of caution.”
Last, Sir Michael Rowe CBE QC, the second president of the Lands Tribunal, in a paper read at a sessional meeting of the Chartered Auctioneers’ and Estate Agents’ Institute in February 1968, said:
“A successful expert witness must begin by appreciating what is his duty to the tribunal as well as his duty to his client. Obviously he has got to do his best for his client just as has a barrister or solicitor and it is not too difficult to do this if you put your mind and heart really into the job. What is sometimes much more difficult is to combine the achievement of that duty with another duty, that is your duty to the tribunal.
“An advocate has a duty not to mislead the tribunal in any way: if discussing the law, he must not fail to inform the tribunal of any case of which he knows that appears contrary to his argument — he must tell the tribunal of it and then do his best to distinguish it from those that he considers to be in his favour. In discussing fact he must not “twist” any evidence, though he can put the most favourable construction on it: he must put before the tribunal in evidence all the facts favourable or unfavourable which are known to him.
“But the expert witness is not an advocate: he is in an even more responsible position, for he is the person who provides the facts and gives the evidence. If he keeps secret a relevant fact he is doing wrong, for it is his duty to assist the court to a proper decision
“There is an old Latin tag, Suppressio veri, suggestio falsi. (If you suppress the truth you may well be suggesting that something you know to be false is true.) Sometimes it is not easy to decide whether a known fact is relevant, in which case it is your duty to disclose it, or whether it is plain prejudice or a red herring giving out a scent which the tribunal ought not to follow. My view is ‘If in doubt disclose and explain.’ Most courts are reasonably sane and tend to be sympathetic to a witness disclosing a difficulty and seeking to overcome it. All courts distrust a witness who is not frank and thereby a lot of perfectly good evidence can be weakened.
“The same sort of attitude should prevail if under cross-examination a witness realises he has made a mistake even if only a partial mistake. Then it is far more profitable to make an admission when cornered than to prevaricate or to think up some reason to justify your position other than the one you have given and relied upon.
“For a witness honesty is always the best policy. Get a reputation for not being quite straight and in a nicely balanced conflict of evidence or opinion you will not be given the benefit of any doubt.”
