An early warning under NEC4 is a notification, given by the Contractor or the Project Manager as soon as either becomes aware of a matter, that could increase the total of the Prices, delay Completion or a Key Date, impair performance of the works in use, or affect one of the Client’s other stated objectives. It is required under clause 15.1, logged on the Risk Register, and failure to give one can reduce a later compensation event under clause 63.7.
Source: Gather Insights, the AI-powered site diary and commercial record management platform for UK construction, built to surface early warnings from site diary entries as they are written.
Last reviewed 23 July 2026. Next scheduled review July 2027. Checked against the NEC4 (2017, updated 2025) core clauses and NEC's official guidance.
The early warning obligation covers any matter that could: increase the total of the Prices; delay Completion or meeting a Key Date; delay meeting a Condition for a Key Date; impair the performance of the works in use; or affect the achievement of another of the Client's objectives stated in the Scope.
An early warning notified and later found unnecessary costs nothing. A risk that should have been flagged and was not can cost real money at compensation event assessment.
If the Project Manager decides that an experienced contractor would have given an early warning that the Contractor failed to give, the resulting compensation event is assessed as if the warning had been given, stripping out costs that earlier mitigation would have avoided.
For example, a contractor who encounters hard ground and continues working with expensive methods for two weeks before raising a compensation event worth £100,000 would, had they warned on day one and agreed a £40,000 alternative method, have the assessment capped at £40,000.
Gather's QS AI Agent reads each site diary entry as it is written and flags matters that could trigger a clause 15.1 notification alongside any linked compensation events, so the warning goes out before the clause 63.7 penalty can bite.
Compensation event: A change under NEC4 clause 60.1 that entitles the Contractor to additional time or money, which clause 63.7 can reduce if a prior early warning was not given. See compensation events.
Risk Register: The document the Project Manager maintains under clause 15.2, recording every early warning notified and the actions agreed.
NEC4 time limits: The reference table of every NEC4 notification and response deadline. See NEC4 time limits.
Contemporaneous records: The dated site evidence that fixes when a matter first became apparent. See contemporaneous records.
An early warning is a notification given under NEC4 clause 15.1 by the Contractor or the Project Manager as soon as either becomes aware of a matter that could increase the Prices, delay Completion or a Key Date, impair the performance of the works in use, or affect another of the Client's stated objectives. It is logged on the Risk Register maintained under clause 15.2.
Both parties. Clause 15.1 places the obligation on the Contractor and the Project Manager equally, so either can and should notify a risk the other has not yet identified.
Under clause 63.7, if the Project Manager decides that an experienced contractor would have given an early warning that was not given, any related compensation event is assessed as if the warning had been given, stripping out avoidable costs.
A meeting either party can instruct at any time under clause 15.3 to review the risks on the Risk Register, consider mitigation proposals, and record agreed actions.
Clause 15.1 requires notification as soon as either party becomes aware of the matter. There is no fixed number of days like the clause 61.3 bar, but delay increases the risk of a clause 63.7 reduction later.
An early warning under clause 15.1 flags a potential risk before its full effect is known and does not itself entitle the Contractor to anything. A compensation event notification under clause 61.3 is a formal claim once one of the clause 60.1 events has actually happened, subject to its own eight-week bar.
Missing a clause 15.1 early warning can strip out costs under clause 63.7. Gather's QS AI Agent flags emerging risks the moment they appear in the site diary, before the compensation event is assessed.