High Court holds parties not bound by expert determination due to “manifest errors”

In WH Holding Ltd v E20 Stadium LLP [2025] EWHC 140 (Comm), the High Court held that parties were not bound by an expert determination, relying on a clause in the contract which allowed the determination to be set aside if it contained a “manifest error”. 

The Court considered previous decisions on the meaning of “manifest error” and concluded that the test was whether the error was "so obvious and obviously capable of affecting the determination as to admit of no difference of opinion".  

Successful challenges to expert determinations are rare, and the exploration of the meaning of “manifest error” in this judgment shows that the bar to challenge experts’ decisions – if this is provided for in the contract at all – remains high. The decision also provides helpful guidance on what a court can review when deciding whether there has been a manifest error in the determination. 

Background

The case concerns a concession agreement between the claimant, WH Holding Ltd (WHH), and the defendant, E20 Stadium LLP (E20) relating to the use by West Ham United Football Club (the Club), of the London Stadium at the former Olympic Park.  WHH was the holding company for the Club. A dispute arose in relation to an additional “Stadium Premium Amount” allegedly payable to E20. The parties disagreed over whether the relevant clause had been triggered by a series of transactions affecting the ownership of the Club. WHH considered that no amount was due; E20 claimed that under the agreement a payment of £3.6 million was payable. In accordance with the agreement, the dispute was referred for expert determination which would be final and binding in the absence of manifest error. The expert accepted E20’s calculation. WHH applied to court for a declaration that the parties were not bound by the determination because it contained two manifest errors.

Decision

Meaning of “manifest error”

Paul Mitchell KC (sitting as a High Court judge) found that the expert had made two errors in his determination. Having found that the expert had made these errors, the judge went on to consider whether these constituted “manifest errors” which would allow the determination to be overturned. Earlier cases have shown this to be a high hurdle, with previous definitions of “manifest error” including “one that is obvious or easily demonstrable without extensive investigation” (IIG Capital LLC v Van Der Merwe [2008] 1 All ER (Comm) 435). The judge relied on the guidance from the Court of Appeal in Veba Oil Supply & Trading GmbH v Petrograde Inc [2002] 1 All ER 703 on whether an error is obvious or easily demonstrable. He concluded that to be “manifest” the error must be “so obvious and obviously capable of affecting the determination as to admit of no difference of opinion”.  The judge observed that the often pejorative or subjective language in previous cases – “blunder”, or the even more colourful “howler” were unhelpful, and would require a purely subjective judgment. 

In terms of the materials a court should review in making its assessment, what constitutes an “extensive investigation” will depend on the context. In some expert determination scenarios, the contract may make clear that a certificate, for example, is conclusive, and that will limit the investigation further.  In this case, the judge focused on the concession agreement and the submissions made to the expert.

Application to the facts

Applying the above test to the facts, the expert had erred in accepting the blended calculation put forward by E20. Qualifying Transactions within the agreement were listed on a disjunctive basis. The expert had misconstrued “or” as “and” in considering the types of Qualifying Transaction. Further, the use of two different values for “A” in the calculation formula, was “an impossible step” with “no basis in the rules”. The errors were obvious and were unlikely to admit a difference of opinion because the determination involved applying the words and formula in the agreement. Further, the errors were obviously capable of affecting the determination because without them, E20’s claim would have been rejected. 

The judge granted a declaration that the parties were not bound by the determination. E20 has appealed and the appeal hearing will take place in May 2026.

Key takeaways 

Expert determination can be a relatively quick and cheap method of resolving a dispute and is particularly suitable where, for example there is a requirement for a non-legal expert to measure the quantity or quality of a product or of work done, or to assess completion accounts or earn-outs in the context of M&A transactions.

However, parties should be aware of the finality of expert determinations and the limited options for recourse. In the absence of “manifest error” or other contractual carve-outs, avenues for challenging an expert determination are very narrow (limited to cases of fraud or failure to comply with instructions). This decision also illustrates the narrow scope of the “manifest error” exception written into expert determination clauses. Successful applications to set aside expert determinations are fairly unusual.

If parties do opt for an expert determination clause, it should be drafted as carefully as possible and specify the grounds on which the determination can be challenged.  Expert determination can be one of multiple dispute resolution options, giving parties the chance to consider its suitability for the dispute that has arisen in practice. Alternatively, disputes as to the construction of the contract may be expressly carved out from expert determination.

In deciding on the most appropriate dispute resolution forum, expert determination may not always provide a significantly quicker and cheaper option to conventional arbitration, including in more general commercial disputes involving issues of contractual construction. The increasing availability and adoption of expedited arbitration procedures (for example allowing for a sole arbitrator and truncated procedure), enables arbitration to be tailored, especially for disputes involving more discrete points. By appointing an “expert” and not an arbitrator, parties also give the person deciding their dispute a considerable amount of additional leeway (absent clear wording to the contrary), for example to conduct their own investigations and form their own views, independently of the parties’ submissions.  That inherently increases the risks and variables of the process and its outcomes, with no increase in the parties’ recourse should mistakes be made.  These are all issues to consider when deciding on the most appropriate dispute resolution procedure for the issues that may arise and who will be best placed to determine them.

With thanks to Imogen Duke for her assistance in drafting this post