ACAS Early Conciliation

The mandatory gateway to an employment tribunal. Before you can submit a claim you must first contact ACAS — and what happens during that process can settle your case, pause your deadline, or arm you with the certificate you need to proceed.

Is ACAS Early Conciliation compulsory before an employment tribunal claim?

Yes, for almost all employment tribunal claims. Before submitting an ET1 form you must first notify ACAS and obtain an Early Conciliation certificate. The only exceptions are claims that specifically exclude the requirement — for example, some interim relief applications, certain national security matters, and a handful of other listed exceptions in the 2014 Regulations. For the vast majority of claims, including unfair dismissal and discrimination, the requirement is absolute.

How long does ACAS Early Conciliation take?

ACAS has up to one calendar month from the point it contacts the other side to attempt conciliation. Both parties can agree to extend that period by up to a further 14 days — making a maximum of around six weeks of active conciliation. If the other side refuses to engage, ACAS can issue the certificate sooner. Once the period ends, with or without a settlement, ACAS issues the Early Conciliation certificate.

What does the Early Conciliation certificate actually say?

The certificate contains a unique reference number — the EC number — along with the names of the parties, the date ACAS received your notification (Day A), and the date the conciliation period ended (Day B). Those two dates are used to calculate your extended tribunal deadline. You must enter the EC number on your ET1 form; the tribunal will reject a claim without it.

Does ACAS Early Conciliation stop the clock on my tribunal deadline?

Yes. The time limit for bringing a tribunal claim is paused from Day A (the day ACAS receives your notification) to Day B (the day the certificate is issued). After Day B you have either the remainder of your original time limit or at least one month — whichever is longer — to submit your claim. The pause is automatic; you do not have to apply for it.

What is a COT3 agreement?

A COT3 is a binding settlement agreement drawn up by ACAS when the parties reach a deal during Early Conciliation. Unlike a settlement agreement, a COT3 does not require the employee to take independent legal advice — ACAS acts as the neutral intermediary, and both sides sign a short document recording the agreed terms. Once signed, the agreement is final and bars any tribunal claim on the settled issues.

Can I contact ACAS more than once about the same dispute?

Generally, you notify ACAS once per prospective claim and receive one EC certificate. If a new act of discrimination or dismissal occurs after the certificate is issued, that later act would need its own ACAS notification. Using the same certificate to cover a new, separate incident is not permitted. If you are unsure whether your circumstances are a continuation of the original complaint or a new one, consider taking advice before notifying.

What ACAS Early Conciliation is — in plain English

Before 2014, bringing an employment tribunal claim was a straightforward two-step process: something went wrong at work, and you filed. Parliament decided that too many cases reached tribunal that could have been resolved without one, and the cost — to claimants, employers and the public — was unnecessary. The solution was to insert a mandatory conciliation stage. Since 6 May 2014, with very limited exceptions, you cannot submit an ET1 claim form unless you have first been through ACAS Early Conciliation and received an EC certificate.

The process begins when you notify ACAS — by phone or online form — that you are considering an employment tribunal claim. You give your name, the name of the prospective respondent (usually your employer), and a brief description of the dispute. ACAS then contacts the other side. If both parties are willing to engage, a neutral ACAS conciliator assists discussions for up to one calendar month. Both sides can agree to extend that period by a further 14 days, giving a maximum of around six weeks. The conciliator is not a judge and not your advocate. They cannot advise you on the strength of your case or tell you what is a fair settlement. They can help both sides communicate when direct contact has broken down, and they can draft a COT3 agreement if a deal is reached.

If the other side refuses to engage

, or if the conciliation period ends without agreement, ACAS issues an Early Conciliation certificate. This document — containing a unique EC reference number — is your authorisation to file a tribunal claim. You enter the EC number on your ET1 form, and the tribunal will not accept a claim without it.

If a settlement is reached

, the terms are recorded in a COT3 agreement. A COT3 is a legally binding contract brokered by ACAS, and it bars any future claim on the settled issues. Unlike a settlement agreement (sometimes called a compromise agreement), a COT3 does not require you to take independent legal advice before signing — the involvement of ACAS satisfies the statutory requirement for the waiver to be enforceable. For this reason, employers often prefer COT3s for speed; employees should read the terms carefully before signing because the waiver can be broad.

One of the most practically important features of the process is what it does to your time limit. For most employment tribunal claims the deadline is

three months less one day

from the act complained of. That period is paused from the day ACAS receives your notification (known as Day A) until the day the EC certificate is issued (Day B). Your new deadline is calculated by adding the number of days between Day A and Day B to what would otherwise have been your filing deadline. If the extended deadline would still leave you less than a month to file from Day B, you automatically get at least one month from Day B. The mechanism is designed so that using Early Conciliation never leaves you with a shorter window than you would have had.

The practical consequence is significant. If you notify ACAS with a week left on your clock, you do not have to rush to file the moment conciliation fails. The clock pauses the moment you notify, and restarts — with at least a month still remaining — when the certificate is issued. This is one reason why it is sensible to notify ACAS promptly, even if you are not certain you want to proceed to tribunal. Notifying does not commit you to anything.

The exemptions from the requirement are narrow. They include claims where a tribunal is directing the proceedings as part of an existing case, some interim relief applications (which must be made within seven days of dismissal and cannot wait), appeals from other jurisdictions, and a small number of other statutory exceptions listed in Schedule 1 of the 2014 Regulations. Equal pay claims — which have a six-month time limit from the end of employment — are subject to Early Conciliation in the same way as other claims.

Marcus was dismissed on

. His claim is for unfair dismissal. The base time limit is three months less one day from the effective date of termination, which gives him until

— 19 days before the deadline — Marcus notifies ACAS. That is Day A. ACAS contacts his former employer, but the employer declines to engage. ACAS issues the EC certificate on

Original filing deadline

Day A (ACAS notification)

Day B (EC certificate issued)

Days paused (Day A to Day B)

New extended deadline

Marcus now has until 8 June 2026 to file. He has 19 days from Day B — more than enough to prepare his ET1 carefully. If the employer had engaged and the full six weeks of conciliation had run without agreement, the pause would have been approximately 42 days, giving Marcus until around 12 July 2026.

Notice that early notification protects Marcus completely. Had he waited until the last day and then notified ACAS, the clock would still have paused — but he would have had the pressure of knowing the deadline was suspended only by that thin margin. Notifying early costs nothing and provides a meaningful buffer.

Employment Tribunal Time Limit

Employment Tribunals Act 1996, s.18A

Employment Tribunals Act 1996, s.18B

Employment Tribunals (Early Conciliation: Exemptions and Rules of Procedure) Regulations 2014

ACAS — Early Conciliation

gov.uk — Make an employment tribunal claim

ACAS Early Conciliation — the mandatory step before a claim

ACAS Early Conciliation explained: why it is compulsory, how the process works, how it pauses your time limit, and what an EC certificate is.

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