FINALITY AND THE LIMITS OF CHALLENGE IN EXPERT DETERMINATIONS
Finality and the limits of challenge in expert determination: the English Court of Appeal in WH Holdings v London Stadium [2026] EWCA Civ 53 reaffirms the high threshold for challenging expert determination on ground of “manifest error”
In WH Holding Ltd v London Stadium LLP (“WH Holding”), the English Court of Appeal revisited the narrow scope for challenging expert determinations on the basis of “manifest error”.
The decision is a clear reaffirmation of finality of an expert’s determination, that is even a wrong answer will stand unless it is obviously wrong.
Background. The dispute arose out of a concession agreement entered into between the claimant, WH Holding Limited, and the defendant, London Stadium LLP, in relation to the London Stadium.
The agreement contained an “overage” provision entitling the defendant to share in value realised from share disposals by the claimant.
The dispute between the parties concerned the application of the overage provision to a transaction which took place in November 2021.
Pursuant to that transaction, the claimant sold shares to a third party, and the third party also benefitted from a call option to purchase additional shares in the future. The third-party paid GBP 18 million as consideration for the right to the call option.
The key question was whether the sums paid for the right to the call option should be included when calculating the overage payable to the defendant.
The agreement contained an expert determination clause. Notably, the clause stated that the determination “shall (in the absence of manifest error) be final and binding”.
Subsequently, the matter was referred to an expert who held that the sums for the call option was included in the calculation for the overage payable. The claimant then challenged that determination before the English High Court.
The first instance judge reversed the expert’s determination, finding that the expert’s calculation “was the result of two obvious errors that would admit of no difference of opinion”: see [2] of the WH Holding.
The defendant then appealed the order.
The Court of Appeal’s decision. The central question that the Court of Appeal had to decide was this: when does an error in contractual interpretation amount to a “manifest error”?
The Court reviewed past authorities which grappled with the meaning of manifest error. After reviewing them, it held that “an error will be manifest if, after investigation limited in time and extent, it is so obvious (and obviously capable of affecting the determination) as to admit of no difference of opinion”: see [45] of WH Holdings.
In other words, an arguable error is not enough, even if that affects the ultimate determination.
The Court held that the first instance judge’s interpretation (as opposed to the expert’s interpretation) was arguable and possibly correct, but that was not the relevant test. Further, the Court held that the expert’s approach to interpreting the terms of the agreement was an arguable one: see [74]-[75] of WH Holdings.
The Court therefore held that the expert’s approach was “not so obviously wrong as to admit of no difference of opinion”: see [78] of WH Holdings.
The position in Singapore. The Singapore Court’s position is identical to the position taken by the English courts. This is largely because the past authorities referred to in WH Holdings were also relied upon by the Singapore court in The Oriental Insurance Co Ltd v Reliance National Asia Re Pte Ltd [2009] 2 SLR(R) 385 (“The Oriental Insurance”).
Notably, according to The Oriental Insurance, “the notion of “manifest error” has also been interpreted … to be “a patent error on the ‘face’ of the award or decision” where the court does “not stray beyond the actual report or award in considering how or why the decision was reached”.”: see [87] of The Oriental Insurance.
Although the Singapore judgment uses different terminology, the legal test is identical in substance: the error has to be so obvious that there would be no disagreement over it.
Key takeaway. The decision in WH Holdings is a reminder that courts will not easily set aside an expert’s incorrect determination unless it can be shown that the error was obvious. The test for “manifest error” remains a high threshold.
For parties opting for expert determination, the decision is a reminder that finality comes at a price, and the courts will hold them to that bargain.
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