ACAS Early Conciliation: Complete Guide

Since 6 May 2014, anyone wishing to bring most types of employment tribunal claim must first notify ACAS and go through the early conciliation process. This requirement was introduced by the Enterprise and Regulatory Reform Act 2013 and is set out in s.18A of the Employment Tribunals Act 1996.

The purpose is to give parties the opportunity to resolve their dispute without the cost, delay, and stress of tribunal proceedings. ACAS reports that around a third of cases are resolved during early conciliation, saving both parties significant time and expense. The process is entirely free and confidential.

If you file an ET1 without an ACAS early conciliation certificate number, the tribunal will reject your claim. There are very limited exceptions — for example, claims involving multiple claimants where another claimant has already notified ACAS about the same employer.

You can start early conciliation by completing the online form on the ACAS website or by telephoning the ACAS helpline on 0300 123 1100. You will need to provide your name and contact details, your employer's name and address, and a brief description of your complaint.

The date you submit your notification is important because it is the date that "stops the clock" on your tribunal time limit. For most claims, the time limit is 3 months minus 1 day from the act complained of. The clock pauses on the day ACAS receives your notification and restarts the day after you receive your certificate.

You should notify ACAS as early as possible, particularly if you are close to the time limit. Even if you are unsure whether you want to go to tribunal, starting early conciliation preserves your right to do so while you consider your options.

Once ACAS receives your notification, a conciliator will be assigned and will contact you (usually by telephone) to discuss the dispute. The conciliator is impartial — they do not take sides or give legal advice. Their role is to facilitate communication and help both parties explore settlement options.

The conciliator will also contact your employer. If the employer is willing to engage, the conciliator will relay offers and counteroffers between you. Common settlement terms include a sum of money, an agreed reference, and a non-disclosure clause. Everything discussed during conciliation is confidential and inadmissible at tribunal.

The initial conciliation period is one calendar month from the date ACAS receives your notification. If the conciliator believes there is a prospect of settlement, they can extend this by up to 14 days. If no settlement is reached within this period (up to 6 weeks maximum), ACAS will issue the early conciliation certificate.

If you reach a settlement through ACAS conciliation, the terms are recorded on a COT3 form. A COT3 is a legally binding agreement that, once signed, prevents you from pursuing the same claim at tribunal. Unlike an ordinary settlement agreement, a COT3 does not require the employee to have received independent legal advice.

COT3 agreements typically include a payment amount, when it will be paid, any tax treatment, an agreed reference, and confidentiality provisions. The ACAS conciliator will ensure both parties understand and agree to the terms before finalising the COT3.

Before signing a COT3, consider carefully whether the terms are acceptable. Once executed, you cannot reopen the claim even if you later feel the settlement was too low. It is worth seeking legal advice if you are uncertain, particularly if the sums involved are significant or the terms include post-employment restrictions.

The early conciliation process extends your time limit for filing an ET1 in two ways. First, the clock is paused ("stopped") from the date ACAS receives your notification (Day A) until the date the certificate is issued (Day B). This paused period is added back to your remaining time.

Second, if your original time limit would expire within one month of Day B, it is automatically extended so you have at least one calendar month from Day B to file your ET1. This ensures you always have a reasonable window after conciliation ends.

For example, if you were dismissed on 1 January and notified ACAS on 15 March (with the original deadline of 31 March), and the certificate was issued on 5 April, you would have at least until 5 May to file your ET1. The rules can be complex, so calculate your deadline carefully or seek advice from ACAS or Citizens Advice.

If conciliation does not result in a settlement, ACAS will issue an early conciliation certificate confirming that conciliation has been attempted. This is not a failure — it simply means the dispute could not be resolved at this stage. Many meritorious claims proceed to tribunal after unsuccessful conciliation.

Once you have your certificate, you can file your ET1 claim form with the tribunal. You must include the ACAS early conciliation certificate reference number on the form. The tribunal will verify this number before accepting your claim.

Even after the certificate is issued and you have filed your ET1, ACAS conciliation remains available throughout the tribunal process. Many cases settle after proceedings have been issued, often at a preliminary hearing or shortly before the final hearing. The ACAS conciliator can continue to facilitate discussions at any stage if both parties are willing.