There have been several judgments in the first few months of 2017 that are worth considering in relation to the impartiality and independence of an expert, as well as the duties of experts.

Construction disputes are frequently technical in nature and depend upon expert evidence. Often, expert evidence is necessary to establish whether a claim exists at all. As a result, an expert may be instructed early, before any decision has been made as to whether the dispute should be referred to arbitration, litigation or even adjudication. When a matter is decided, the arbitrator, court or adjudicator will often depend on the expert evidence in reaching conclusions.

The effect of appointing experts early

In Lalana Hans Place Ltd v. Michael Barclay Partnership LLP [2017] EWHC 29 (TCC), engineering advisers had been appointed in relation to the defendant's work. The engineering advisers' advice led to remedial works. At the same time, the claimant instructed an expert engineer for legal proceedings to recover the costs of implementing the remedial works. Coulson J observed that it is not "uncommon for a litigation expert, who is involved early in the relevant decision-making process, to give advice as to what should be done or not done. That advice may then be a matter of fact relevant to, for example, a decision to demolish or, as in this case, a decision to carry out costly remedial works".

A week before trial, the defendant made an application requiring the claimant to provide further information relating to the advice given by the claimant's expert at the time the decision was taken to undertake remedial work. The request specifically concerned the advice, contact, comment, and sharing of information between the advisers and the expert, and any involvement the expert had in the decision to undertake remedial work. Coulson J ordered the claimant to answer the request, although he could not determine at that stage whether privilege might apply.

The judgment is a reminder to keep the roles of project adviser and litigation expert separate. In later proceedings all communications between the advisers and the expert will be disclosable if they are relevant to the decisions taken during the project and, ultimately, to the case. It may be sensible to instruct experts for litigation after advisers have provided opinions on remedial solutions (although bear in mind that the litigation expert might not agree with the remedial solution and his/her view on the appropriate remedial solution may need to be set out in any expert report to the court).

Can an expert act for the defendant, having acted for the claimant?

Wheeldon Brothers Waste Ltd v. Millennium Insurance Company Ltd [2017] EWHC 218 (TCC) was a claim in which the claimant sought to recover £1.5 million damages from insurers (Millennium) following a fire. Millennium declined to accept liability under the insurance policy. The claimant applied to the court, seeking to prohibit Millennium from relying on its chosen expert's evidence.

The expert in question had been originally instructed by Millennium to investigate the cause of the fire, and had attended the site the day after the fire. On the basis of the expert's investigations and findings, Millennium declined liability under the insurance policy.

As the claim under the insurance policy had been rejected, the claimant then approached Millennium's expert to assist in its attempted recovery against third parties. Against this background, Millennium's loss adjusters gave permission for the claimant to instruct the expert. The claimant's solicitors instructed the expert, making clear that his instruction was to assist "with [the claimant's] proposed recovery" against third parties, and he produced a report. A copy of this report was later served with the claimant's letter of claim against Millennium. Formal proceedings then began, and Millennium then instructed the expert as its expert witness in the case.

Coulson J ruled that there was no basis for preventing Millennium from relying on the expert. This was because: (i) the expert attended immediately after the fire, so was in the best position to assist the court with its inquiry; (ii) there was not any overlap or conflict between what the expert had done for Millennium and for the claimant; (iii) Millennium instructed the expert under the relevant part of the Civil Procedure Rules, meaning that the expert's overriding duty was to the court (not to the party that instructed him); and (iv) no confidential information had been shared.

An expert's independence

This brings us to a recent Court of Appeal judgment, EXP v. Barker [2017] EWCA Civ 63. The subject matter of this case was a medical negligence claim, but the judgment contains an important reminder of the need for an expert to be independent. It came to light at trial for the first time (during cross-examination) that there was a connection between the defendant and the defendant's expert witness. They had worked together for a number of years, and, in fact, the expert witness had trained the defendant. It also became clear that the defendant had suggested the expert should be appointed.

The Court of Appeal upheld the trial judge's decision to take account of this connection when considering the weight to be given to the expert's evidence. The Court of Appeal went further than the trial judge, by indicating that it would have supported the trial judge had he decided to exclude the expert's evidence entirely. The Court of Appeal judgment notes that our legal system "depends heavily on the independence of expert witnesses, on the primacy of their duty to the Court over any other loyalty or obligation, and on the rigour with which experts make known any associations or loyalties which might give rise to a conflict."

Parties should ensure they are aware of, and have investigated, any potential conflicts of interest or connections prior to instructing an expert. If there is a conflict of interest or a connection, this should be disclosed to the other party (or parties) as early as possible. Failure to do so, while potentially innocent, may result in the exclusion of or diminished weight being applied to the evidence, with consequences to that party's case.