It is not unusual for a construction case to stand or fall on the quality of the evidence given by independent expert witnesses, who are retained to address issues of liability and/or quantum. The judgment given by Coulson J in the TCC case of Van Oord UK Limited and SICIM Roadbridge Limited v Allseas UK Limited provides a useful reminder to those instructing experts that, not only must an expert witness have the requisite technical ability and experience in their field, they must also have a proper understanding of their duties to the court.

Van Oord UK Limited and SICIM Roadbridge Limited v Allseas UK Limited

At trial, each party called a quantum expert to give evidence.  In his judgment, Coulson J was highly critical of the claimants' expert who he considered had "allowed himself to be used" by the claimants "to act as their mouthpiece".  Coulson J went on to say that, it was almost as if the claimants were "trying to see how much of their claim they could get past [the Claimants' expert], and [the Defendants' expert] and ultimately the Court" such that "it made a mockery of the oath which [the Claimants' expert] had taken at the outset of his evidence".  This culminated in the claimants' expert making "an abrupt departure from the witness box at a short break for the transcribers, never to return".

Coulson J was keen to point out that he had endeavoured to give the claimants' expert the benefit of the doubt as he was dealing with a serious illness in his family and had never before prepared a written expert's report or given evidence in the High Court.  Nevertheless Coulson J considered his evidence was "entirely worthless" such that he was obliged to disregard it "in full".

The points made by Coulson J to justify his conclusion serve as a useful aide memorie to those instructing experts who should take steps to ensure that any expert witness they retain:

  1. Does not take the pleaded claims at face value and properly checks the underlying documents to ensure they can be substantiated.
  2. Considers the witness statements prepared on behalf of both parties.  One party's statements should not be treated by the expert as a contemporaneous record of events.
  3. Critically analyses the claim and considers points raised by the other party's expert.
  4. Does not use their report to try to plug gaps in a party's witness evidence.  The views in an expert's report should be their own and, where they are not, this should be made clear. 
  5. Identifies work product/analysis undertaken by others and the extent to which they have taken steps to verify this information and/or documentation and challenge it.


Finding and retaining the right expert can be difficult and time consuming, but the importance of this task and undertaking appropriate due diligence checks should not be underestimated.  It is often the most important step in a case, along with continuing to supervise and monitor that expert.

Van Oord concerns an extreme set of facts; however, Coulson J's judgment serves as a stark warning of the risks of using an expert who is inexperienced, not properly supervised/monitored and/or who does not properly understand what the court requires of them. 

Key to this is the overarching principle that an expert's duty to assist the court overrides any obligation to the person instructing or paying them.  Accordingly, anything which suggests that an expert is not impartial or has failed to act independently will damage their credibility and may lead to their evidence being entirely discredited.  This may prove fatal in cases which rely heavily, or turn, on expert evidence.