A recent case in the business and property court provides lessons for both expert witnesses and their instructing parties. The judge was disappointed by the quality of the evidence from several experts but also highlighted flaws in the way they were instructed, gaps in the evidence and the timing of their written reports.
In Craigard (Dartford) Ltd & Anor v Westbury Homes (Holdings) Ltd & Anor [2026], the claimants pursued a commercial tenant for damages of £1,609,125.53, comprising £1,335,980.15 for remedial works, £218,145.38 for loss of rental income, and £55,000 for professional fees, on an office building.
His Honour Judge Keyser KC ultimately awarded £648,141.47, around 40% of the sum claimed. This was largely because the claim had not adequately considered alternative remediation, such as repair over replacement. Nor had the experts addressed this alternative in their reports.
Incomplete instructions
The judge highlighted various issues that caused the experts to be less well appraised of the situation than they should have been. The defendant’s surveyor, for example, had not been given access to inspect the premises, nor had he seen witness statements or disclosed documents that were seen by the claimants’ building surveyor.
Likewise, the defendant’s engineering expert had seen just one report – the BWB report – before writing his original report. The BWB report summarised the findings of a mechanical and electrical dilapidations investigation of the heating, ventilation and air-conditioning (HVAC) system. He subsequently gained access to additional evidence, but the judge said his report was then “clumsily” updated, and the extra evidence did not materially inform the revised report.
Experts’ failure to produce a joint statement
The judge was particularly dismayed by the two experts’ failure to produce the joint statement that had been mandated by the case management orders. Instead, they produced separate commentaries on each other’s findings, followed by responses to those commentaries.
The judge said: “I did not find that helpful at all. I do not regard the evidence of either expert as very satisfactory. It does not help that neither of them had the opportunity to inspect the HVAC system, so that they both have to form their opinions on the basis of third-party materials.”
Further issues with the expert evidence
Commenting on the evidence of the claimants’ engineering expert, the judge said he had “a tendency to rely on what was unknown … as showing that repair was a minefield and so not feasible”. This, the judge added, “has in turn a tendency to reverse the burden of proof”.
Because the expert had not considered the feasibility or cost of repair, or whether repair would have met the tenant’s obligations, the court lacked the evidence it needed to weigh those arguments.
This mattered all the more because the BWB report, which the judge considered the most reliable documentary evidence, recommended repairing the HVAC system rather than replacing it.
The claimants’ expert had also produced a report after the proceedings were brought but backdated it and wrote it as though it had been produced at that earlier date. The judge described the report as a “reconstruction” and said that the expert had never been instructed to consider whether repair was a viable option.
The defendants’ expert, meanwhile, was criticised for arguing that every component of the system had to be in disrepair before full replacement could be justified. The judge found this ‘implausible’ and noted that the argument became muddled under cross-examination.
Lessons for experts and instructing parties
This case highlights the importance of experts being given complete instructions and having access to all the relevant documentation. While instructing solicitors are responsible for providing all relevant documents, experts who believe material evidence exists but have not seen it can, and should, ask for it.
Once they are in possession of the facts, they have a duty to form an opinion purely based on established fact and must consider all realistic alternative outcomes, whether or not they are contrary to the client’s preferred position.
In addition, where a court mandates the production of a joint statement, that requirement must be met. Experts should be aware of what a joint statement is, and what it is not, and be able to meet the requirement when asked to do so.
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