Expert witnesses from opposing sides may be ordered to meet before the trial to discuss their opinions on the dispute. But they shouldn't then be asked to reveal what was said.
A recent construction case called Robin Ellis Ltd v MalWright Ltd (February 1999) gives some very good guidance for all you architects, engineers, surveyors and the like who dabble in the expert evidence business. Particularly helpful is the fact that it points up new rules that will apply to experts in court actions from 26 April 1999.

I will come to the case in a moment. First, let me remind you how much reliance a judge or arbitrator places on the expert witness. Nowadays, they tend to trust you. They rely on you to be even-handed, impartial and quite capable of telling your client to sling his hook when he or his solicitor tries to coax you into saying something not quite tickety-boo.

Once, though, the courts thought you to be charlatans. Sir George Jessel, the Master of the Rolls, said 125 years ago: "I very much distrust expert evidence. In the first place, although the evidence is given on oath, the [expert] knows he cannot be indicted for perjury, because it is only evidence as to matter of opinion. A dishonest man, knowing he could not be punished, might be inclined to indulge in extravagant assertions …

"That is not all. Expert evidence is evidence of persons who … are remunerated for the evidence. An expert is not like an ordinary witness, who hopes to get his expenses, but he is employed and paid in the sense of gain, being employed by the person who calls him."

This very senior judge was discussing bias, of course, and referred to experts as paid agents of the person who employs them. This suspicion, I think, lasted until recently. Then began a determined effort by people such as the RICS, the Official Referees Solicitors Association and the Bar to construct a code of conduct that elevates the status of the expert. It is now a respectable commercial task.

What Robin Ellis v MalWright provides is another strand of guidance. It tackles first what goes on when a court or arbitrator orders that opponent experts meet pre-trial to discuss their opinions on the quarrel. For example, the issue might be how to value variations. They will, ultimately, be ordered to draw up a joint statement saying what is agreed, what requires further research and what is not agreed. That statement becomes available as evidence. But what is not to be revealed to the tribunal is what the experts said to each other. All this is kept secret, for the very good reason that they should be free to discuss the issues without this being in any way thrown in their face.

Neither expert should be pressured by his client. Nor should any arbitrator ask, or allow, questions about what went on

The judgment also touches on the occasional problem where a solicitor instructs the expert not to agree anything without first referring to the solicitor. The court is firm on this: "The party to the litigation cannot properly tell the expert what evidence he is to give under oath in court, nor can he tell the expert what opinion to express in documents produced by him."

The judge pointed to recent comments by the current Master of the Rolls, Lord Woolf. Meetings can be futile if the experts are told not to agree anything. "This subverts the judge's intention of directing the experts to meet, because the decision as to what to agree becomes a matter for the lawyers rather than the experts." Lord Woolf said it should be "unprofessional conduct for an expert to be given or to accept instructions not to agree".

The case also settles the question of whether the experts' agreement binds the parties. No, it does not. It remains open to any lawyer to explain facts that cast doubt on what the two experts might have agreed. Nothing binds the parties unless this power is expressly given to the experts by the parties. The judge pointed to the rules coming in April: "Where experts reach agreement on an issue during their discussions, the agreement shall not bind the parties, unless the parties expressly agree to be bound." He said: "I regard that rule as stating the law."

The case highlights the usefulness of experts meeting. Their discussions are out of sight and sound of the tribunal. Once finished, the joint statement is available as evidence. Neither expert should be pressured by his client. Nor should any arbitrator ask or allow questions about what went on prior to the statement.