Is it illegal not to pay a subcontractor?
No, it is a breach of contract rather than a criminal matter, but the Construction Act gives the unpaid subcontractor fast remedies that do not need a court.
Updated: 15 September 2026. By Jack Butler-Kettle, Quantity Surveyor & Claims Consultant.
The answer
No. Failing to pay is a breach of the contract, not an offence, so there is no authority to report it to. What the law gives you instead is quicker than a court. If the payer gave no valid notices, the notified sum is the sum you applied for and it is due on the final date for payment. Once that date passes unpaid you may, after giving the notice the Act and the contract require, suspend performance until payment, with the time and reasonable cost of the suspension recoverable. Statutory or contractual interest runs on the late amount. And the dispute can be referred to adjudication at any time, with a decision that binds the parties until finally determined and is enforced by the courts as a matter of course. The order matters: establish the notified sum first, because every later step is stronger when the sum is not in dispute. Rights and remedies beyond the commercial position are for a solicitor.
Example
The situation
A subcontractor has applied for £38,000, no notices have been received, and the final date for payment passed ten days ago. The commercial position is that £38,000 is the notified sum and is overdue.
What happens
- A written demand goes out recording the missed notices and the final date.
- Interest is calculated from the day after the final date.
- A suspension notice follows if payment does not.
- Adjudication follows if payment still does not arrive.
The outcome
The £38,000 is pursued as the notified sum, overdue since the final date, through those steps in that order.
The Emergency Notice Desk checks the notice position the same day if a deadline is close.