Wembley: Expert evidence from in-house professionals

The main judgment in the Wembley case dealt with a number of legal issues [see link]. One which we have considered is the question of “entire contracts”, and how this affects the right to be paid [see link]. The issue we consider in this article is whether an employee of a party (or of a related company) may give expert evidence in court proceedings. In Wembley the principal engineer of one of Cleveland Bridge’s subsidiary companies gave evidence on expert technical matters and factual issues in the case. Multiplex said his evidence on expert matters should be rejected.

Why was there an issue?

In a word: objectivity. Expert witnesses have an overriding duty to assist the court. This duty applies ahead of any other duty the expert may have to other people. The underlying approach of this “overriding duty” concept is to ensure that useful evidence finishes up before the court. Evidence may be helpful if it is given independently and objectively. On the other hand it will be unhelpful to the court if an expert deliberately skews his evidence in a party’s favour, simply because the expert is being paid by that party, or for some other reason.

In most cases the question of objectivity and independence is not an issue. There are many professional expert witnesses who although paid for their work are not employees of the parties who engage them. They assist the court by focussing on the issues in dispute in a non-partisan manner. But there are often cases, especially in technical fields where there are not many professional expert witnesses, where the people with real expertise are those who have an interest (directly or indirectly) in the outcome of proceedings. In one sense this was true of the principal engineer who gave evidence for Cleveland Bridge. He was employed within the Cleveland Bridge group. But did this mean his evidence on expert matters was not admissible, because he was not independent or objective?

Admissible

The court said his evidence was admissible, but the weight given to the evidence was affected by his lack of independence. The principal engineer clearly had expertise and experience in matters of structural engineering, and his evidence on those matters was helpful to the court. However, the judge also said that the partisan nature of his evidence reduced its credibility.

Helpfully, the court gave two examples of when it might be appropriate for a factual witness who is an interested party (such as the principal engineer in this case) to give expert evidence:

• Where the witness’s expert opinion is reasonably related to his factual evidence. For example, an engineer may explain the remedial scheme implemented for a project, both as a matter of fact and also as to why it was technically sound.
• Where the witness has relevant experience related to his factual evidence. For example, an engineer may refer to his previous experience in implementing such a remedial scheme.

In summary: there is no blanket rule that expert evidence cannot be given by an employee or other person who has an interest in a party to court proceedings. The court may admit the evidence, but the weight of the evidence may be reduced if the witness is not entirely objective in his evidence.

Reference: Multiplex Constructions (UK) Ltd v Cleveland Bridge UK Ltd (No.6) [2008] EWHC 2220 (TCC) (see Chapter 4)