Prevention principle and time at large in England and Wales

For the general doctrine see the neutral extension of time page; for the English framework, the England and Wales hub.

The principle is a default allocation, and clear words displace it

The status question is settled. In North Midland Building Ltd v Cyden Homes Ltd [2018] EWCA Civ 1744 the Court of Appeal (Sir Terence Etherton MR, Sir Ernest Ryder SPT and Coulson LJ, who gave the lead judgment) upheld a bespoke amendment to JCT Design and Build 2005. Clause 2.25.1.3(b) provided that "any delay caused by a Relevant Event which is concurrent with another delay for which the Contractor is responsible shall not be taken into account". Coulson LJ held that the principle is not "an overriding rule of public or legal policy" (¶30), and that a term implied to stop the employer levying liquidated damages for the concurrent period would contradict the express terms (¶45).

So the principle governs only where the parties have said nothing. The live question is one of construction: what does this contract, as amended, say about this event?

Multiplex gives the working test, and the qualifier in the first limb matters

The modern statement is Jackson J's in Multiplex Constructions (UK) Ltd v Honeywell Control Systems Ltd (No 2) [2007] EWHC 447 (TCC) at ¶56:

1. "Actions by the employer which are perfectly legitimate under a construction contract may still be characterised as prevention, if those actions cause delay beyond the contractual completion date" (¶56(i)).
2. Acts of prevention by an employer do not set time at large if the contract provides for extension of time in respect of those events (¶56(ii)).
3. "In so far as the extension of time clause is ambiguous, it should be construed in favour of the contractor" (¶56(iii)).

The first proposition is often quoted without its last clause, and the clause does real work: a legitimate variation instruction is prevention only if it pushes completion beyond the contract date. The second is why the doctrine so rarely succeeds: where the contract extends time for the employer's acts, they move the date instead of destroying it. The third is why employers draft extension clauses widely, though Jackson J added that it "must be treated with care": the lean is towards a construction that lets the contractor recover appropriate extensions of time (¶57), not towards time at large.

The classical cases explain the gap that modern forms close

The older authorities, in paraphrase, are background to Multiplex, not the test.

Prevention must be prevention in fact

Causation. In Adyard Abu Dhabi v SD Marine Services [2011] EWHC 848 (Comm) Hamblen J required "prevention in fact; not prevention on some notional or hypothetical basis" (¶264). An employer act that would have delayed an unimpeded contractor does not engage the principle if, because the contractor was already late for its own reasons, it made no actual difference to completion. Employers argue further that a contractor already in critical delay cannot be prevented at all; North Midland left that unresolved (¶¶17 to 18), so it is an argument, not settled law (see concurrent delay). So a contractor running prevention needs the same delay evidence as one claiming an extension.

Scope. BNP Paribas Depositary Services Ltd v Briggs & Forrester Engineering Services Ltd [2024] EWHC 2903 (TCC) is the most useful recent statement of what prevention is. HHJ Stephen Davies held that an act of prevention may be a breach of an express or implied obligation or the exercise of an entitlement, such as giving an instruction (¶192). What it is not is the occurrence of an event whose risk the contract has already allocated. At ¶193 he adopted Adyard: the conduct must make timely performance "impossible or impracticable" and must actually prevent the contractor carrying out the works. On the facts, the contractor's suspension and termination failed, because the asbestos survey and structural supports it said the Employer had failed to provide (¶207) were within its own design and build risk.

Two cautions. BNP Paribas is sometimes cited as limiting prevention to breaches of contract; ¶192 says otherwise. And the case decided a suspension right under cl 8.9.2 of an amended JCT Design and Build 2016. It construes "prevention" in the JCT phrase "impediment, prevention or default", which is also the cl 2.26 wording relied on below, by reference to the common-law cases (¶193). It is not a time-at-large decision.

Why time at large is rarely won under JCT and NEC4

The contractor must show an act of prevention, which in fact delayed completion, which the contract does not deal with. The standard forms are built to defeat the third hurdle.

Three points close the remaining routes.

The sweep-up event answers Peak. Where the form extends time for employer impediment, prevention or default, or treats Client breach as a compensation event, little is left outside the machinery and Multiplex ¶56(ii) applies. Under NEC4 a lawful Client act that is not a breach must still fit another listed event (Inference.). Ambiguity in the sweep-up helps the contractor argue scope (¶56(iii)), not time at large.

A contractor cannot use its own failure to notify. In Multiplex Jackson J saw "considerable force in Professor Wallace' criticisms of Gaymark" and had "considerable doubt that Gaymark represents the law of England" (¶103). He distinguished Gaymark Investments Pty Ltd v Walter Construction Group Ltd [1999] NTSC 143 at ¶104 without finally deciding whether it represents English law. The working position in England is that a contractor who misses a condition-precedent notice is time-barred, not released from the date (see notice and time bars). Under NEC4 that means cl 61.3 is not side-stepped by calling a late-notified Client breach prevention (Inference.). For how Australian courts have treated Gaymark since, see prevention and time at large in Australia.

Errors in operating the clause are not failure of the clause. A late, low or nil JCT award (there is no deemed grant) is a dispute about the award, which the post-completion review and adjudication exist to correct. In Mace Construct Ltd v Baltic Investment Holdings Ltd [2026] EWHC 976 (TCC) the court confirmed that an adjudicator "can open up, revise and review" the extension granted and carries out "a prospective assessment" under the clause (¶50). A machinery that can be corrected has not broken down, so a tribunal is unlikely to treat a missed 8-week deadline as setting time at large (Opinion.). The route is set out on adjudicating extensions of time.

Contracts can move the risk further, and Mace shows the drafting

Amended contracts routinely move delay risks the printed forms leave with the Employer (Opinion.). In Mace the contract was an amended JCT Design and Build 2016, in which the statutory approvals Relevant Event sat at cl 2.26.13 (¶36(b)). An amended cl 2.1.3 placed the risk of obtaining consents on Mace and excluded an extension under cl 2.25 for it (¶36(a)). The court refused declaration 6, on planning and consents risk, as muddled and highly fact-sensitive (¶¶38 to 41), so the case illustrates drafting; it decides nothing about where consents risk fell.

The point for prevention is the one BNP Paribas ¶192 makes: an event whose risk the contract gives to the contractor is not an act of prevention, and North Midland confirms that such an allocation is enforceable. Gateway 2 and Gateway 3 approval delay on higher-risk buildings is the obvious 2026 candidate (Opinion.) (current medians are on the hub). Check the DB 2024 number for the statutory approvals event against the executed contract.

Where it still bites: requirements outside the machinery, and conduct

Two 2026 decisions show the principle is alive; read them for what they decided.

UK Global Healthcare Ltd v Secretary of State for Health and Social Care [2026] EWHC 561 (TCC) concerned contracts for the supply of gloves. Constable J dismissed DHSC's applications for summary judgment on its £15.35m counterclaim and to strike out UKGH's claim. UKGH's argument that DHSC's conduct had put time at large was not pleaded (¶31). The judge restated the principle, citing Trollope & Colls and Adyard (¶32), and held it arguable that pre-delivery testing requests which DHSC had no right to make under the original contracts prevented timely delivery and put time at large (¶87). He also found a real prospect that the parties' exchanges met the "something more" that Rock Advertising Ltd v MWB Business Exchange Centres Ltd [2018] UKSC 24 requires before conduct can override a no-oral-modification clause (¶86).

Durkan Estates Ltd v Wallace Estates Ltd [2026] EWHC 2003 (TCC) arose under a Building Safety Act remediation agreement. The freeholder terminated for anticipatory breach and failed to obtain reverse summary judgment (¶¶44, 69). Constable J held it plainly arguable that both parties had proceeded on the basis that completion would follow regulator approval, not the contract date, so that an estoppel by convention would stop the freeholder relying on that date and, on the developer's case, leave time at large (¶¶41, 43).

Neither case is a finding that time was at large: both are interlocutory, and UK Global Healthcare is not a construction contract. The shared pattern: requirements imposed outside the contract's risk machinery, which no Relevant Event or compensation event covers, and conduct that sets the contractual date aside. In my assessment those are where a time-at-large plea has real prospects on an English project in 2026 (Opinion.).

If time is at large, the employer loses its liquidated damages but not its claim

• The date goes, and so does the liquidated damages clause. With no operable date to measure from, the liquidated damages machinery cannot run (Peak).
• The contractor must complete within a reasonable time, a question of fact on all the circumstances.
• The employer can still sue. It recovers general damages for failure to complete within a reasonable time, proving breach and loss in the ordinary way (Rapid Building).
• Termination does not wipe out accrued liquidated damages. In Triple Point Technology Inc v PTT Public Co Ltd [2021] UKSC 29 the Supreme Court held that liquidated damages accrue up to termination; they are not lost because the work was never completed.

The double edge. Where the liquidated damages rate was also the limit of the contractor's liability for delay, setting time at large can expose the contractor to general damages with no cap, measured on the employer's actual loss. Model the downside before pleading it, and check whether the contract caps delay damages separately from the liquidated damages clause (Opinion.).

What is not settled

The status of the principle is settled at Court of Appeal level, and the Multiplex propositions are the working test. Three related things are not. There is no reported English judgment construing the JCT 2024 extension of time provisions [NEGATIVE FINDING, searched 13 October 2026]. The default rule for concurrent delay, where prevention arguments most often collide with contractor delay, rests on first-instance authority; see concurrent delay. And the two 2026 time-at-large arguments in UK Global Healthcare and Durkan v Wallace have not been decided at trial; no later judgment in either was located as at 13 October 2026.

Where Storia fits

Every prevention argument on this page turns on two records: what the employer actually required, and what that requirement did to the critical path at the time. Storia turns correspondence, instructions, programmes and site records into one source-linked project record, so a team can show whether a demand sat inside or outside the contract, and whether it delayed completion in fact rather than in theory.

Sobre este material El contenido de la biblioteca es información general sobre la práctica de las reclamaciones de construcción, no asesoramiento jurídico. El derecho a reclamar, los plazos y el procedimiento se rigen por su propio contrato y por el derecho del lugar donde se ejecuta la obra. Revisado el 13 de octubre de 2026 · Informar de una corrección