If you carry out construction work in the UK, the Housing Grants, Construction and Regeneration Act 1996 (as amended by the 2009 Act), known as the Construction Act, gives you payment rights that override what a harsh contract might otherwise say. Here are the parts that matter most to a subcontractor.
A right to interim payment
For contracts lasting more than 45 days, you are entitled to stage or interim payments, not just one payment at the end. The contract must contain an adequate payment mechanism; if it does not, the Scheme for Construction Contracts fills the gaps.
Payment notices
After the payment due date, the payer must issue a payment notice within five days, stating the sum they consider due and how it is calculated, even if that sum is zero. If they fail to, your application can stand as the default payment notice.
The pay-less notice
If the payer wants to pay less than the notified sum, they must serve a pay-less notice before the final date for payment, setting out the reduced sum and why. No valid pay-less notice means they must pay the notified sum in full. Many "smash and grab" payment claims succeed precisely because the payer missed this notice.
The right to suspend
If you are not paid the notified sum by the final date for payment, you have a statutory right to suspend performance, in whole or in part, after giving at least seven days' written notice. You are entitled to your reasonable costs of suspending and remobilising, and to an extension of time.
Adjudication
You can refer a dispute to adjudication at any time. It is a fast process, usually 28 days to a decision, designed to keep cash flowing while bigger disputes are resolved later.
Keep on top of the dates
These rights live or die by deadlines. Track every due date, payment notice and pay-less deadline on each project. For how payment applications feed into this, see applications for payment vs invoices.
This is general information, not legal advice. For a specific dispute, take professional advice.