Authored by: Gary McGifford for Rimkus EMEA
Published 5/29/2026
For litigation solicitors, claims managers and loss adjusters working on NEC-governed disputes — how the Accepted Programme, early warning notices and compensation events interact, and why entitlement so often turns on procedure rather than merits.
What are NEC contracts?
Thomas Telford Ltd, the commercial arm of the Institution of Civil Engineers, publishes NEC drafted by Dr. Martin Barnes. The first edition was published in 1993, with NEC2 published in 1995, and NEC3 published in 2005. The current edition, NEC4, was published in June 2017, with amendments in January 2019, October 2020 and January 2023. The Cabinet Office endorses NEC4 for public-sector procurement, which is why it dominates UK infrastructure and public works projects.
The contract suite spans works, services and supply contracts. In dispute work, four matter most: the ECC (main works), the PSC (professional services), the TSC (term services) and the SC (supply). Each ECC is assembled from one of six main options — A and B priced, C and D target cost with pain/gain, E and F cost reimbursable — plus a dispute resolution option (W1, W2 or W3), secondary X options and any bespoke Z clauses. The Client procures the works; the Project Manager administers the contract; the Supervisor monitors quality; and the Contractor builds.
Inadequate contract administration is the leading cause of adjudicated construction disputes in the UK. In the third King’s College London and Adjudication Society report (November 2024), half of all respondents named it as a principal underlying cause — ahead of every other factor.
On NEC projects, poor administration carries unusual weight. The NEC4 Engineering and Construction Contract (ECC) combines time and money entitlement into a single compensation event procedure, measures delay against a rolling Accepted Programme and imposes an eight-week notification time bar that can extinguish entitlement altogether. A claim that would survive under JCT can fail under NEC solely on timing grounds.
This article explains how the three mechanisms interact, where disputes come from, and what that means for assessing exposure.
The short version
- The Accepted Programme is the baseline. Compensation event delay is measured against the Accepted Programme current at the Dividing Date (Clause 63.5). No current Accepted Programme, no reliable compensation event assessment.
- Eight weeks or nothing. Under Clause 61.3, a Contractor who fails to notify a compensation event that they are required to notify, within eight weeks of becoming aware that the event has occurred, may lose their entitlement entirely. The clause operates as a condition precedent (a “time bar”).
- Early warnings have teeth. Miss an early warning an experienced Contractor would have given, and the compensation event is assessed as if the warning had been given (Clause 63.7), which can limit the allowable time and costs. On cost-based options, that cost can also be disallowed.
- NEC4 tightened the machinery. Deemed programme acceptance, the Dividing Date and disallowed-cost sanctions all sharpen the consequences of poor administration compared with NEC3.
How does the Accepted Programme drive entitlement?
Everything in the NEC4 ECC time assessment runs through the programme. Under Clause 31.1, the Contractor submits its first programme within the period stated in the Contract Data. Under Clause 31.3, the Project Manager then has two weeks to accept it or give reasons for rejection, and the contract limits valid reasons to the specified grounds. Rejecting a programme for any other reason is itself a compensation event under Clause 60.1(9).
NEC4 added a deemed acceptance mechanism. If the Project Manager fails to respond, the Contractor may notify that failure; if the silence continues for a further week, the programme is treated as accepted. The days of programmes languishing unaccepted for months, common under NEC3, now carry a contractual consequence.
Why does acceptance matter so much? Because Clause 63.5 measures delay as the amount by which the compensation event pushes planned Completion beyond planned Completion in the Accepted Programme current at the Dividing Date. Without a current Accepted Programme, that assessment cannot function as designed, and the Project Manager may end up making their own assessment under Clause 64.1 — rarely a comfortable position for either party. Terminal float (the gap between planned Completion and the Completion Date), which is owned by the Contractor, is generally accepted as unavailable to be consumed to offset the impact of compensation events.
What do early warning obligations require?
The early warning notice is NEC’s risk radar under Clause 15. Both the Project Manager and the Contractor must notify the other as soon as either becomes aware of a matter that could increase the total of the Prices, delay Completion or a Key Date, or, made explicit in NEC4, impair the performance of the works in use. The trigger is awareness of possibility, not certainty, and the test for a Contractor’s failure is objective: could an experienced Contractor have given the early warning?
NEC4 formalised the machinery through an Early Warning Register, maintained and issued by the Project Manager, and regular early warning meetings at which risks are discussed, mitigation is considered, and actions are recorded until the risk is resolved.
The cost of staying silent
Failure to give early warning bites at the compensation event assessment. When issuing a quotation, the Project Manager states whether the Contractor failed to give an early warning that an experienced Contractor could have given (Clause 61.5). Clause 63.7 then assesses the event as if the warning had been given — excluding costs that could have been avoided. On cost-based options (C through F), NEC4 goes further: cost incurred only because no early warning was given is Disallowed Cost. That double exposure has no NEC3 equivalent.
How do compensation events work?
A compensation event is the single gateway to additional time and money under the ECC. Where JCT runs variations, extensions of time, and loss and expense as separate regimes, NEC assesses each event for cost and time together, once — and once implemented, the change to the Prices and dates is final under the contract.
NEC4 lists 21 compensation events in Clause 60.1 (NEC3 listed 19), from instructions changing the Scope (60.1(1)) to breach of contract not covered elsewhere (60.1(18)). Unforeseeable physical conditions (60.1(12)) put ground risk on the Client, judged objectively by what an experienced Contractor would have allowed for at the Contract Date.
The eight-week time bar
For Contractor-notified events, Clause 61.3 provides eight weeks from the date the event is first noticed. Miss it, and entitlement to changes in the Prices, the Completion Date or a Key Date may be lost — the notification operates as a condition precedent. NEC4 also fixed an NEC3 drafting problem by rewording the trigger from ‘of the compensation event’ to ‘awareness that the event has happened’, removing the risk of the clock starting before the event itself.
The Project Manager’s timely reply
Clause 61.4 requires the Project Manager to reply to the Contractor’s notification of a compensation event within one week, though this period can be extended if the Contractor agrees. If the Project Manager fails to reply within the one week (or the extended time agreed), the Contractor may notify the Project Manager of that missed period. If the failure to reply then continues for a further two weeks, it is treated as acceptance that the Contractor’s notification is a compensation event and as an instruction to submit quotations.
The intent of Clauses 61.3 and 61.4 is to make both Parties responsible for keeping the compensation event process moving and to prevent it being excessively delayed.
The Dividing Date
The Dividing Date, new in NEC4, draws a clean line between the records-based and forecast-based parts of the valuation. Assessment follows Clause 63.1: actual Defined Cost of work done by the Dividing Date, forecast Defined Cost of work not yet done, plus the resulting Fee.
Where do NEC disputes actually come from?
In practice, four questions decide most NEC disputes before any expert analysis begins: Did the Contractor notify the compensation event within eight weeks? Was there a current Accepted Programme? Were early warning obligations met? And do the records support the Defined Cost claimed? Weak answers to any of these can reduce or extinguish what looks, on its engineering merits, like a strong claim.
Unresolved disputes follow the route chosen in the Contract Data: Option W2, where the Housing Grants, Construction and Regeneration Act 1996 applies (with adjudication as a mandatory first step); Option W1 where it does not; and, new in NEC4, Option W3, a Dispute Avoidance Board available under the ECC outside the HGCRA.
What this means in practice
- Audit the programme position first. Whether there is a current Accepted Programme — and when it was last accepted — frames every delay assessment that follows.
- Build the notice chronology early. Map every compensation event notification against the eight-week bar, and every early warning against the date awareness arose. Exposure often turns on this table alone.
- Treat records as the claim. Defined Cost assessment is records-based by design. Site diaries, cost records and programme updates are not supporting documents; they are the entitlement.
Rimkus provides independent delay analysis, quantum assessment and expert evidence on NEC3 and NEC4 disputes across the UK and internationally. To discuss a specific matter, contact our EMEA team.
This article provides general information about prevailing industry practice. It is not legal, technical or professional advice and should not be relied on as such. Consult a qualified professional about the specific facts of any matter.