Rung 3 · The required pre-claim step

ACAS & Early Conciliation

5 min read · Reviewed 22 June 2026

Before you can bring most Employment Tribunal claims, you must go through ACAS Early Conciliation. This page explains what it is, why it matters for your deadline, and that many disputes settle here — without a hearing.

What Early Conciliation is

ACAS — the Advisory, Conciliation and Arbitration Service — is a free, independent service. Early Conciliation is a mandatory step: before you can issue most tribunal claims you must notify ACAS, who then offer both sides a chance to settle without going to a tribunal. You do not have to settle, but you must go through the step.

It pauses your time-limit clock

This is the part that catches people out. When you notify ACAS, the clock on your three-month time limit pauses, and there is a minimum window to claim after you receive the certificate. But it only helps if you start it before your deadline — starting ACAS does not revive a deadline you have already missed.

Settling at conciliation (a COT3)

Many disputes resolve at this stage. If both sides agree, ACAS records the settlement in a binding agreement called a COT3. A settlement is often the quickest and least stressful outcome — and stopping here is a success, not a failure.

If it does not settle

If conciliation does not resolve it, ACAS issues an Early Conciliation certificate with a reference number. You need that number to bring a tribunal claim. Conciliation stays open even after you have issued — you can settle at any point.