More questions than answers

“Most of the problems with expert evidence arise because the expert is initially recruited as part of the team which investigates and advances a party's contentions and then has to change roles and seek to provide the independent expert evidence which the court is entitled to expect.”

So wrote Lord Woolf in his interim report, highlighting the need for impartial expert evidence. He seeks to make a distinction between the expert assisting a litigant to advance his case – the expert as “hired gun” – from the expert preparing and giving evidence to the court – the expert as “untouchable truth teller”. The mechanism Lord Woolf suggests to bring this about is to limit privileged communication.

“Once an expert has been instructed to prepare a report for the use of the court, any communications between the expert and the client and his advisers should no longer be privileged…all written and oral instructions received and which are relevant to the contents of the report should be disclosed in the report.”

How will the absence of privilege in communications with experts work in practice? Privilege will apply for instructions to and discussions with experts in the early stages of litigation.

Therefore, the expert will be able to play a full part in investigating the facts, assessing the technical strengths of the case, making a statement of claim or defence and forming part of the team which devises the litigation strategy.

In the course of these discussions, an expert may become aware of weaknesses in the technical aspects of the case – indeed, much of his expertise may be directed to minimising weaknesses. Any communications about those weaknesses should be privileged.

The Rubicon is crossed when the expert receives instructions to prepare a report for the use of the court. He will be referred to the statement of issues and to those issues which his report is required to cover.

Now that his first responsibility is to the court and not the client, will the expert have to refer in his report to the weaknesses he has discussed with the client on a privileged basis? Should he mention these weaknesses even if the other side are not aware of them?

It seems the expert is now in an impossible position. If he mentions the weaknesses this will be a breach of any trust the client reposed in him.

If the prospect of such disclosure was made clear when the expert's appointment was considered then it is highly unlikely the expert would be engaged at all.

On the other hand, if the expert does not mention any weaknesses, will he be subjected to cross-examination over the basis and content of his earlier involvement in the case, before he was formally instructed to prepare an report for the court?

There are other difficulties. Do experts know enough about the law of privilege to decide which communications they ought to disclose?

This may be acute for the expert who only occasionally becomes involved in litigation; they are bound to need guidance on the litigation process and the principles governing discovery of documents, privilege and evidence.

This guidance is commonly given by the solicitors acting for the party which instructs the expert. Will they be able to give this knowing they risk unintended disclosure of privileged information? Will such guidance itself be privileged? Will an expert end up needing his own solicitor?

The alternative of having experts who are litigation experts rather than a professional in their field is also undesirable – it may limit the range of expertise available to the court.

What happens after the exchange of experts' reports? Can you have a privileged discussion with your expert about the other side's report? Can your expert attend a conference with counsel when advice is given on the merits and evidence of the case?

It cannot be intended that any of the views expressed at such a conference should be disclosed by the expert when they later give their evidence to the court.

The idea that an expert can change from hired gun, with the benefits of privileged discussions with the client and his advisers, to untouchable truth teller having main responsibility to the court to disclose all communications is likely to prove unworkable.

If this distinction is maintained, clients will keep hired gun experts as part of their team throughout the litigation and then bring in an untouchable impartial expert when an expert's report is required, only providing them with instructions and information which will not damage their case if revealed in court.

This would increase costs and will provide impartial expert evidence for the court but only on the basis of partial, sanitised information.

An alternative would be to recognise the impossibility of a dual role for experts and press ahead with the proposal for court-appointed experts to act either as experts or assessors. They could provide the court with an expert's view on the reports of the hired guns and, as suggested in Lord Woolf's report, could supervise the meetings of experts which aim to find agreement on as many issues as possible before trial.