Chartered surveyors acting as expert witnesses must provide independent, impartial and evidence-based opinions to assist courts, tribunals and arbitration panels in resolving complex property disputes.
A recent High Court decision, Regal BA Ltd v Zhang [2026] EWHC 1446 (Ch) provides an important reminder of the standards expected of valuation experts and the impact that expert instructions can have on the reliability of their valuation evidence.
In this article, we examine the court's key findings regarding:
- The importance of maintaining independence, transparency and professional conduct as an expert witness.
- How the timing and content of expert instructions can influence valuation evidence and potentially undermine it.
Property dispute: summary
The dispute concerned a luxury residential property in North London that the defendant had agreed to purchase from the claimant developer for £16.9 million. The defendant paid two deposits but subsequently failed to complete the transaction.
Following the final default, the claimant remarketed the property and ultimately sold it for £10,157,168.94.
The claimant brought proceedings against the defendant to recover its loss, calculated as the difference between the agreed contract price and the eventual sale price. The defendant argued that the claimant had failed to adequately mitigate its loss by properly marketing the property following the failed transaction. She also contended that the contractual deposits should be deducted from any damages awarded.
Outcome
The court found in favour of the claimant and awarded damages based on the contractual purchase price of £16.9 million, less the two forfeited deposits.
Expert evidence
A significant aspect of the judgment concerned the conduct and reliability of the expert valuation evidence.
Both parties instructed experienced chartered surveyors who were members of RICS and had each been practising for more than 20 years. Despite their experience and qualifications, HHJ Hacon expressed concerns about the extent to which the expert evidence could be relied upon.
Criticism of the claimant expert
HHJ Hacon identified several concerns regarding the claimant expert's conduct, including:
- Failing to inform the defendant's expert after realising that details relating to a property both experts had treated as a comparable had been incorrectly stated.
- Failing to disclose that his son had visited the property in a professional capacity and any information obtained from that visit to the defendant expert.
The judge also questioned the claimant expert's impartiality and independence, commenting that, in assisting “the court with his honestly held views, [the expert] probably did so with Regal's case well in mind and sometimes felt the need to state his views accordingly”.
By contrast, HHJ Hacon found that the defendant's expert was “more able and willing to make appropriate concessions in cross-examination” than his counterpart.
The judge’s concerns about the instructions provided
The judgment also contains important observations on the information provided to valuation experts on instruction.
Before preparing their reports, both experts knew the value that the party instructing them wished to establish at trial. This information had influenced the experts' respective opinions leading the judge to conclude that the value of the expert evidence, “even as a cross-check”, had been compromised.
A better approach
HHJ Hacon suggested an alternative process that could have reduced the risk of influence from the outset.
In his view, experts should first prepare and serve their reports without being told the valuation figure their instructing party seeks to establish. Once those reports have been finalised and exchanged, the relevant information can then be disclosed.
Experts could subsequently be asked to prepare supplementary reports addressing whether knowledge of the actual sale price or other relevant figures alters any conclusions expressed in their original reports and, if so, why.
In summary
HHJ Hacon's judgment provides valuable guidance for both legal teams and experts involved in property and valuation disputes.
The decision reinforces the importance of independence, transparency and professional conduct when acting as an expert witness. Technical expertise alone is not enough; experts must also demonstrate compliance with all their duties and obligations.
The judgment further highlights the importance of carefully structured expert instructions. Where experts are exposed too early to information that may anchor their opinions, the reliability and weight of their evidence may be diminished.
Ultimately, the case serves as a reminder that the credibility of expert evidence depends not only on the quality of the analysis but also on the integrity of the process by which those opinions are formed.
How we can help
Bond Solon provides training, which covers all the core skills and knowledge expert witnesses are required to fulfil their role compliantly and to best practice standards. We also offer university assessed and certified training programmes that are widely regarded as the industry gold standard by instructing parties.