Court of Appeal finds expert's determination not manifestly in error

The Court of Appeal has held that an expert's interpretation of a contractual clause that determined a party's share of gains arising from a qualifying transaction was not manifestly in error, overturning an earlier High Court decision: WH Holding Ltd v London Stadium LLP [2026] EWCA Civ 153.

The decision confirms that the test for manifest error requires the court to consider whether the error was "so obvious and obviously capable of affecting the determination as to admit of no difference of opinion". The nature of the issue to be determined does not affect the test. It applies both to questions of contractual interpretation and to the interpretation and application of contractual mathematical formulae.

The decision reinforces the final and binding nature of expert determinations. The English courts will interfere only in exceptional cases, where the expert's decision is so obviously wrong as to be unarguable.

For more information see this post on our Litigation Notes blog.