Clerkenwell Lifestyle v HG Construction: be careful what you call "agreed" in extension of time correspondence

Anyone who has sat through the back and forth of extension of time correspondence on a construction project will recognise the language in Clerkenwell Lifestyle (UK) Ltd v HG Construction Ltd [2026] EWHC 1406 (TCC). Emails about "agreeing" extensions, clients giving "approval", and proposals issued "in consideration of" various concessions are the everyday currency of project administration. The case is a sharp reminder that this everyday language, however emphatic it looks months or years later, will not easily be elevated into a freestanding binding contract that displaces the machinery of the building contract itself.

The dispute arose from a 153 room hotel and affordable housing development in Clerkenwell, built under an amended JCT Design and Build Contract. In February 2023, following a 12 week extension of time request, the Employer's Agent emailed HG Construction with a package of proposals covering both this project and a separate office contract, concluding with an offer to issue a 12 week extension of time and revised completion dates. HG replied confirming agreement. The following day, the Employer's Agent issued a formal Notification of Extension of Time under clause 2.25, citing two Relevant Events, and stating it had been issued subject to the terms of the email exchange.

Fast forward to an adjudication over liquidated damages, where the adjudicator awarded Clerkenwell just under £956,000. HG's response, submitted the day after the decision under the guise of a request to correct a "slip", ran to nearly fifteen pages and argued that the adjudicator had used the wrong starting point for his calculations. HG's new case was that the February 2023 email exchange constituted a binding agreement to revise the completion dates, entirely independent of the contractual extension of time mechanism, and that the adjudicator should have added his further extensions to those dates rather than to the original contractual completion dates.

Mrs Justice Jefford gave this argument short shrift on two fronts. On enforcement, she found no breach of natural justice. The supposed binding agreement defence had not, in substance, been raised in HG's Response to the Referral. A single paragraph quoting the February email appeared in a section dealing with an entirely different argument about the scope of the works, and HG's own expert had run his delay analysis from the original contractual completion dates throughout, which was flatly inconsistent with the binding agreement case now being advanced. An adjudicator cannot be criticised for failing to grapple with a defence that was never properly put to him, however inadvertent the omission might have been.

On the Part 8 claim itself, the judgement offers a useful structured analysis of when extension of time correspondence crosses the line into a separate binding contract. The word "agree" in this context most naturally describes the parties operating the contractual mechanism, particularly where a formal Notification of Extension of Time followed the next day citing specific Relevant Events under clause 2.25. The February email was also part of a much broader package of proposals spanning two contracts, several of which were expressly conditional or provisional, making it commercially implausible to extract just the extension of time element as a standalone binding promise. The judge also drew on the established principle that subsequent conduct, while generally inadmissible on construction, can be evidence of whether a contract exists at all, and neither party had behaved as though one did.

There is also a useful coda on agency. Even had a binding agreement existed, the judgement doubts whether an Employer's Agent appointed under Article 3 of a JCT contract would have authority to enter into a separate contract varying completion dates, as opposed to operating the extension of time provisions for which it is appointed. For those drafting or relying on EOT correspondence, the lesson is that formality and precision matter long before any dispute arises, because courts will look hard at how the contractual machinery was actually operated, not just at the words used in the heat of project negotiations.