ACAS Early Conciliation Guide

Complete guide to ACAS early conciliation - the mandatory first step before any Employment Tribunal claim. Learn how it works, timelines, and how it extends your deadline.

Last updated: 14 February 2026

Quick Reference

Duration
Up to 12 weeks
Cost
Free
Contact
0300 123 1100
Required for
Most ET claims

Key Things to Know

Essential
Legal requirement
You must contact ACAS before submitting an ET1 form. The tribunal will reject your claim without a valid Early Conciliation certificate number (s.18A Employment Tribunals Act 1996).
Essential
Time limit extension
The clock stops on your tribunal time limit while you are in early conciliation. This gives you extra time after the process ends.
Important
Certificate number
ACAS will issue a certificate with a reference number you need on your ET1 form. Keep it safe.
Important
Confidential process
Anything said during conciliation cannot be used as evidence at tribunal.
Helpful
Free service
ACAS early conciliation is completely free of charge.

How Time Limits Are Extended

Day A is when you contact ACAS, Day B is when the certificate is issued.

  • If your deadline falls between Day A and Day B, you get at least 1 month from Day B.
  • If your deadline falls after Day B, you get the remaining time plus the conciliation period.

When ACAS Is Not Required

Limited exceptions exist:

  • Claims against the Secretary of State for redundancy payments from the National Insurance Fund
  • Certain other specific claim types

For the vast majority of claims, ACAS is mandatory.

The Early Conciliation Process

1

Contact ACAS

Call 0300 123 1100 or submit the online form at acas.org.uk/early-conciliation. Provide your details and your employer's details.

2

ACAS contacts your employer

A conciliator will contact your employer to see if they are willing to engage in conciliation.

3

Conciliation period

ACAS has up to 12 weeks to help you reach a settlement (the period was doubled from 6 weeks on 1 December 2025).

4

Settlement or certificate

If you settle, ACAS records it on a COT3 form (legally binding). If not, ACAS issues an Early Conciliation certificate.

5

Submit your ET1

Once you have your certificate, submit your ET1 form. Your time limit is extended by the conciliation period.

Tips for Early Conciliation

  • Contact ACAS as early as possible - Don't wait until close to your deadline. Starting early gives you maximum flexibility.
  • Keep your certificate safe - You need the certificate number on your ET1 form. Save a digital copy as well.
  • Be open to settlement - Many cases settle through ACAS. A reasonable settlement avoids the uncertainty of a tribunal hearing.
  • Know your minimum acceptable amount - Before conciliation starts, work out the minimum settlement you would accept.
  • Settlements through ACAS are tax-free - The first £30,000 of a settlement agreed through ACAS is normally exempt from income tax.
  • You don't need a solicitor - ACAS conciliation is designed to be accessible. You can participate without legal representation.

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Frequently Asked Questions

What is ACAS early conciliation?
A mandatory free process where ACAS tries to help you and your employer reach a settlement before you go to tribunal. You must contact ACAS before submitting an ET1 form.
Do I have to go through ACAS?
Yes, for almost all Employment Tribunal claims. The tribunal will reject your ET1 if you do not have a valid Early Conciliation certificate. There are very limited exceptions.
How long does early conciliation take?
ACAS has up to 12 weeks (doubled from 6 weeks on 1 December 2025). If your employer refuses to engage, ACAS may issue the certificate sooner.
Does early conciliation extend my time limit?
Yes. The time spent in ACAS conciliation pauses your tribunal deadline. You get at least 1 month from the date the certificate is issued.
What if my employer refuses to participate?
ACAS cannot force your employer to participate. If they refuse or do not respond, ACAS will issue your certificate so you can proceed with your tribunal claim.
Is early conciliation confidential?
Yes. Anything said during the conciliation process is confidential and cannot be used as evidence at the tribunal. This encourages open negotiation.