A pre-action letter (also called a Letter Before Action or Letter Before Claim) is a formal notice sent to another party before starting court proceedings. It is required by the Civil Procedure Rules (CPR) Pre-Action Protocols for most types of civil claim. You should send one when informal attempts to resolve a dispute have failed and you are considering taking the matter to court — for example, recovering an unpaid debt, pursuing a breach of contract, or claiming for damaged goods.

Under the CPR Pre-Action Protocol for Debt Claims (the most commonly used), the letter must set out the nature and basis of the claim, the amount being claimed, any interest being sought, the evidence relied upon, and give the defendant a clear response deadline — typically 30 days for debt claims. For other claim types, a 14-day deadline is commonly used. The letter must also state that court proceedings will follow if the matter is not resolved.

Not automatically, but it is often effective. Many disputes settle at the pre-action stage because the other party realises you are serious and that court costs would increase their liability. It also puts you in a strong position if you do go to court — a judge will want to see that you followed the correct pre-action procedure, and failure to do so by either party can affect costs orders.

If they do not respond within your stated deadline, you can proceed to issue a claim via the County Court online (via the Money Claim Online service for debts up to £100,000, or MCOL for smaller amounts). For claims under £10,000, the Small Claims Track applies — it is designed to be used without a solicitor and court fees are relatively modest.