ACAS early conciliation

Before you can make most claims to an employment tribunal, you must notify ACAS and go through early conciliation. It is free. A conciliator contacts you and your employer and tries to help you settle the dispute without a hearing. If it does not settle, or either side does not want to take part, ACAS issues a certificate with a number, and you need that number to submit your tribunal claim.

Who has to use it

Early conciliation is required for nearly all claims to an employment tribunal, including unfair dismissal, discrimination, unpaid wages, holiday pay and redundancy pay. A small number of claims are exempt, such as some where another claimant has already conciliated about the same matter, or an urgent application for interim relief in a whistleblowing or trade union dismissal case. If you think you fall into an exception, check with ACAS.

It applies to employees and workers alike, and to people who have already left their job. It also applies across the public sector: an NHS trust, a council, an academy trust or a government department is treated like any other employer.

How it works

1. You notify ACAS, either through the online form or by phone. You give your details and your employer’s details. You do not have to set out your whole case.
2. An ACAS conciliator contacts you to talk about the claim and ask whether you want to try conciliation.
3. If you agree, the conciliator contacts your employer. The conversations are confidential and nothing said in them can be used at a tribunal.
4. If you reach an agreement, ACAS writes it up as a settlement, usually called a COT3. It is legally binding and normally ends your right to bring the claim.
5. If you do not settle, or either side declines to take part, ACAS issues the early conciliation certificate.

The conciliator is neutral. They will not tell you whether your claim is strong, but they can explain how tribunals work and what the other side’s position seems to be. Conciliation is limited in time, so it does not drag on indefinitely.

What it does to the time limit

This is where people get caught out. Most tribunal claims must be brought within a set time limit, which rose from three months to six months on 1 October 2026 (9 November 2026 for contract claims in Scotland). Our guide to employment tribunal time limits covers which claims this affects.

You must contact ACAS before the time limit runs out. Notifying ACAS stops the clock while conciliation is going on, and you then get extra time after the certificate is issued. The exact calculation depends on the dates, and getting it wrong can end a claim before it starts. If your deadline is close, notify ACAS straight away and work out the new date from the certificate as soon as you get it.

The certificate number must go on your tribunal claim form. Claims submitted without a valid number, or with details that do not match, can be rejected.

Internal procedures first

Early conciliation does not replace your employer’s own procedures. In most cases you should still raise a formal grievance, or appeal a disciplinary decision, before or alongside going to ACAS. Under the ACAS Code of Practice on disciplinary and grievance procedures, a tribunal can adjust an award by up to 25 per cent if either side unreasonably fails to follow it. If you skip the grievance stage without a good reason, any compensation could be reduced.

Public sector employers usually have detailed written grievance and disciplinary policies, often agreed with unions. Our guides to raising a grievance and disciplinary procedures explain how they normally work. Waiting for an internal process to finish does not pause the tribunal time limit, though, so keep an eye on the date.

Settling: COT3 and settlement agreements

A COT3 agreed through ACAS is binding as soon as both sides agree, even before it is signed in some cases. Read the terms carefully. It can include money, an agreed reference, a confidentiality clause and a statement that you will not bring other claims.

A settlement agreement is a different route. It is agreed directly with your employer, and for it to be valid you must have independent legal advice, which employers often pay for. Either route can end a dispute, but neither can stop you reporting wrongdoing as a whistleblower.

Getting help

ACAS runs a free helpline and its website explains the process. Your union can represent you in conciliation and often at tribunal. If your dispute is about discrimination, our guide on discrimination at work points to further help. If the problem is an unlawful deduction from pay, start with deductions from wages, because many pay problems can be fixed through payroll before anyone needs ACAS.