No Frolic, No Foul: Natural Justice in Coventry & Warwickshire Development Partnership LLP v Avison Young (UK) Ltd [2026] EWHC 2319 (TCC)

On 15 September 2026, Eyre J handed down judgment in Coventry & Warwickshire Development Partnership LLP v Avison Young (UK) Ltd [2026] EWHC 2319 (TCC) (“CWDP v AY”), granting summary judgment to enforce an adjudication decision awarding approximately £8.73 million and interest as damages for professional negligence. Jonathan Lewis KC, instructed by Joseph Hale of Eversheds Sutherland (International) LLP, appeared for the successful Claimant. The judgment provides important guidance on the permissible scope of adjudicator initiative, the procedural safeguards required when departing from the parties’ positions, and the proper limits of severance arguments in enforcement proceedings.

The dispute arose from the development of an industrial park at Gateway South, Coventry. The Claimant (“CWDP”) engaged the Defendant (“AY”) as NEC project manager and supervisor in relation to earthworks. CWDP alleged that AY had significantly over-certified amounts due to the earthworks contractor by accepting reduced baseline volumes without question, relying on the contractor’s progress data without proper interrogation, and failing to identify defects [3–5].

The adjudicator structured his analysis around the stages of the certification process rather than separating breach, causation, and loss into distinct sections [69]. Where the parties’ experts disagreed, he placed reliance on the “G&T Assessment” (a post-termination valuation by Gardiner & Theobald), which fell between the two experts’ figures [57, 79], ultimately concluding that AY had failed to carry out its duties to the required standard of skill and care and awarded £8,729,179.33 inclusive of interest [47–48]. AY refused to pay and resisted enforcement on four principal grounds:

1. The adjudicator had failed to address the referred dispute, instead conducting a valuation exercise rather than determining professional negligence [64]. Eyre J rejected this. The adjudicator correctly identified the issue, found the criticisms of AY’s performance valid at paragraphs 5.30–5.39 of the Decision, and expressed his conclusion by reference to the standard of skill and care (at paragraph 5.160). His rejection of certain defects claims (at paragraph 5.109), distinguishing between over-payment and breach, was “very far from being solely an exercise in valuation” [68]. AY’s related argument based on Bratt v Jones [2025] EWCA Civ 562 was held at best to show the adjudicator addressed “the right question in the wrong way” [71].
2. The adjudicator had failed to give adequate reasons for his decision [49]. Eyre J rejected this: the detailed critique mounted by AY itself demonstrated the reasons were sufficient to enable the parties to understand what had been decided and why [53]. Further, there was a limit as to what reasons needed to be given. It was not necessary for the adjudicator to give reasons for his reasons.
3. There were material breaches of natural justice [74]. AY’s principal ground was the adjudicator’s reliance on the G&T Assessment, which neither party had advanced [79]. Eyre J held the issues had been “fairly canvassed”: the adjudicator identified the assessment as potentially relevant, explained why, invited submissions, offered a meeting (declined), and indicated he was minded to rely on it [81–82]. Such an approach was “wholly consistent” with Roe Brickwork Ltd v Wates Construction Ltd [2013] EWHC 3417 (TCC) at [23]–[24] [83]. No further iterative round was required [84]. On the retention and defects sub-grounds raised by AY, Eyre J held that the adjudicator’s approach was “a classic example” of permissible Roe Brickwork reasoning: weighing each party’s contentions and accepting aspects of each [87–88].
4. Even if the Decision was enforceable as a whole, parts should be severed [89]. AY argued the retention and defects findings should be severed on natural justice or manifest error grounds [90–91]. Eyre J rejected this: what AY sought was not true severance but a recasting of one finding and recalculation of the total. This was inconsistent with the binding nature of adjudicators’ decisions [97]. Citing Hutton Construction Ltd v Wilson Properties (London) Ltd [2017] EWHC 517 (TCC) and paragraph 10.4 of the TCC Guide 2026, he confirmed that challenges to part of a decision require Part 8 proceedings [94]. Further, severance is permissible only where discrete sums can be excised without disturbing the remainder; here, the retention finding was part of a continuous chain of reasoning [96–97].

The contrast with another recent adjudication enforcement decision Premier Modular Ltd v Maidstone and Tunbridge Wells NHS Trust [2026] EWHC 1404 (TCC) is instructive: there, Adrian Williamson KC sitting as a Judge of the High Court, held that the adjudicator “went off on a ‘frolic’” by finding a compensation event under a contractual provision neither party had advanced [42]. In CWDP v AY, by contrast, the issues had been fairly canvassed throughout. The message is clear: considerably more frolicking than occurred here is required to vitiate an award.

CWDP v AY is one of several recent TCC decisions addressing enforcement, alongside Premier Modular, Darchem Engineering Ltd v Bouygues Travaux Publics [2026] EWHC 220 (TCC), and High Tech Construction Ltd v WLP Trading and Marketing Ltd [2026] EWHC 152 (TCC). Read together, these decisions confirm that the TCC’s pro-enforcement stance remains intact: where enforcement has been refused, it is because the adjudicator materially departed from the issues referred, decided on an unargued basis, or lacked jurisdiction: orthodox, well-established grounds. The threshold for resisting enforcement remains high, and ordinary errors of fact, law or reasoning will not suffice.

That having been said, CWDP v AY is interesting and important because the Judge made a distinction between two types of notice that an adjudicator might give when considering relying on evidence/argument that neither party had advanced. An adjudicator would typically be required to give the parties notice of such an intention and give them a fair opportunity to make submissions so as to avoid a potential breach of natural justice. However, an adjudicator would not typically be required to give the parties an additional opportunity to make further submissions on the approach that the adjudicator has decided to adopt. The requirement for a ‘two-staged process’ was rejected by the Judge given that it would likely prolong the period of the adjudication.  

For practitioners, the practical lessons arising from CWDP v AY are threefold:

1. For referring parties, the priority is to ensure that the adjudication is properly framed and that the adjudicator’s jurisdiction is secure before the referral is made.
2. Responding parties should engage substantively with any indication from an adjudicator that a new evidential or analytical route is under consideration, including by advancing alternative positions, rather than maintaining a single position and bearing the consequences if it is rejected. In particular, Eyre J observed that AY could have advanced a subsidiary case on the footing that the G&T Assessment was relied upon but chose not to [84]. That decision proved costly.
3. For adjudicators, a warning: if a new route to a decision emerges during the reference that neither party had previously advanced, the parties must be given a fair opportunity to address it before it is adopted.

A copy of the Judgment can be accessed here.

Case note written by Katy Handley.