If you’re thinking about making a claim against an employer — or you’ve just received a letter saying a former employee is considering one — you may have already come across a name that sounds bureaucratic but matters enormously: Acas. Before almost any employment tribunal claim can even be lodged, both sides are required to go through a process called Early Conciliation. Skip it, get the timing wrong, or misunderstand what it actually offers, and you can lose your right to claim altogether. This guide explains what Acas Early Conciliation is, how it works, and what it means for your tribunal deadline.
Acas Early Conciliation Explained (UK): The Step Before a Tribunal
What Is Acas Early Conciliation, and Why Is It Mandatory?
Acas — the Advisory, Conciliation and Arbitration Service — is an independent, publicly funded body that helps resolve workplace disputes without the need for a tribunal hearing. Early Conciliation (EC) is the specific process that sits between a workplace dispute and the formal start of an employment tribunal claim. For almost every type of claim, including unfair dismissal and constructive dismissal, the law requires the person bringing the claim (the claimant) to notify Acas first.
This is not an optional courtesy step. In the vast majority of cases, a tribunal will not accept an ET1 claim form unless it is accompanied by a valid Early Conciliation certificate number. That number is proof that you went through the process, and without it your claim can be rejected on a technicality before anyone even looks at the substance of your dispute.
The purpose behind the rule is straightforward: many workplace disputes can be resolved — through an apology, a reference, a payment, or simply clarity on both sides — without the cost, delay, and stress of a full tribunal hearing. Acas conciliation gives both parties a structured, low-pressure opportunity to explore that before things escalate further, often while a related grievance procedure has already run its course internally.
How Early Conciliation Actually Works
You start Early Conciliation by submitting an EC notification form to Acas, which can be done online in a few minutes, or by calling the Acas helpline if you prefer to talk it through. You’ll need basic details about yourself, the employer, and a brief outline of the dispute. There is no fee to notify Acas and no fee for any stage of the conciliation process itself — it is entirely free to both the employee and the employer.
Once Acas receives the notification, an Acas conciliator will make contact, usually by phone, with the person who raised it, and then with the other party if there is an interest in exploring settlement. It is worth being clear about what the conciliator's role actually is: they are impartial. They do not represent either side, they do not take sides in the dispute, and critically, they do not give legal advice or tell either party who is likely to win if the case went to tribunal. Their job is purely to facilitate conversation and, where both sides are willing, help reach a voluntary agreement.
Everything discussed with an Acas conciliator is confidential and cannot generally be used as evidence later if the case does proceed to tribunal. This is deliberate — it allows both sides to speak candidly about settlement figures or concerns without worrying that an offer or a concession will be held against them in a later hearing.
You are never obliged to settle. Either party can simply say the dispute cannot be resolved this way, and conciliation ends. There is no penalty for declining to settle, and nothing about the process affects your underlying legal rights if you choose not to reach an agreement.
The Six-Week Period and the Effect on Your Tribunal Deadline
Early Conciliation has a standard period of up to six weeks from the date Acas receives your notification, though it can end earlier if both parties agree a settlement, or if either side confirms there is no prospect of resolving matters informally. At the end of this period, whether or not anything was agreed, Acas issues an Early Conciliation certificate with a unique reference number.
This is where the interaction with your tribunal deadline becomes genuinely important, and where people most often trip up. Most tribunal claims — unfair dismissal among them — must normally be brought within three months less one day of the relevant date, such as the date of dismissal or the act being complained about. Early Conciliation applies a “stop the clock” mechanism to that limit: broadly, the normal time limit is paused for the period you spend in conciliation, and there is a further mechanism that can extend your time to submit a claim once the certificate is issued, so that going through EC does not itself eat into the time you have to bring a claim.
That said, the exact calculation depends on precisely when you contacted Acas relative to your original deadline, and getting this date wrong is one of the single most common reasons genuine claims are thrown out before they are even heard on their merits. Do not try to calculate your own deadline from memory or from a general description like this one — check the specific dates that apply to your case on GOV.UK or directly with Acas, and if there is any doubt, get advice well before time runs out rather than after.
Because the clock only pauses once you notify Acas, contacting them as soon as you know you may have a claim is far safer than waiting until the deadline is close. Leaving it late gives conciliation less room to work and leaves less margin for error in your own date calculations.
What Conciliation Can Achieve: COT3 Agreements and What Happens if It Fails
If both sides reach agreement during Early Conciliation, the terms are typically recorded in a document called a COT3. A COT3 is a legally binding settlement, negotiated with the help of an Acas conciliator, and once signed it normally prevents the same claim being brought again at tribunal. This is a genuinely different route from a settlement agreement signed with independent legal advice, which is the other main way UK employment disputes are settled outside a hearing — a COT3 does not require the employee to take independent legal advice before signing, whereas a formal settlement agreement legally must involve that step to be valid.
A COT3 can cover many of the same things a settlement agreement might: a financial payment, an agreed reference, confirmation of the termination reason, and confidentiality terms, all shaped around what actually matters to the two people or organisations involved rather than what a tribunal judgment would order.
If no agreement is reached, whether because the parties are too far apart, one side declines to negotiate, or the dispute simply cannot be resolved informally, Acas closes the conciliation and issues the Early Conciliation certificate. At that point you are free to proceed to submit an ET1 claim form and continue toward a tribunal hearing, using the certificate number as part of that submission. Nothing about an unsuccessful conciliation weakens your underlying claim.
It is also worth knowing that Acas involvement does not end permanently at this stage. Further conciliation can and often does happen after a claim has been formally lodged, right up until a final hearing, since most tribunal disputes that do settle end up settling at some point before they reach a judge.
Practical Points While You Are Going Through Conciliation
You do not need a solicitor to take part in Early Conciliation, though there is nothing stopping you getting independent advice on your position, your likely claim value, or a proposed COT3 figure before you agree to anything. Because a COT3 is binding once signed, it is sensible to understand roughly what you are giving up and what you are gaining before agreeing to any figure, even informally over the phone.
Going through conciliation, or having an unresolved dispute with a former or current employer, does not stop you from applying for other jobs or starting new ones in the meantime. In fact, many people going through this process find that having their job search moving forward in parallel takes real pressure off the negotiation itself — you are not forced to accept a weak offer purely out of financial urgency. Atlas can help with exactly that: Create a free Atlas account to keep your job search active and organised while a workplace dispute plays out, so you have options regardless of how the conciliation ends.
This guide is general information only and is not legal advice. Time limits, eligibility, and the effect of conciliation on your specific case depend on your exact circumstances, so verify your deadline on GOV.UK or with Acas directly, and speak to Citizens Advice or a qualified employment solicitor if you are unsure how any of this applies to you.
Frequently Asked Questions
Is Acas Early Conciliation compulsory?
Yes, for almost all employment tribunal claims. You must normally notify Acas and receive an Early Conciliation certificate before a tribunal will accept an ET1 claim form, with only limited exceptions set out in law.
How long does Early Conciliation take?
The standard period is up to six weeks from when Acas receives your notification, though it can end sooner if a settlement is reached or if either party confirms conciliation will not resolve the dispute.
Does Early Conciliation pause my tribunal deadline?
Broadly, yes — the usual three-months-less-one-day time limit is paused while conciliation is ongoing, with a further extension mechanism once the certificate is issued. The exact dates depend on your case, so always verify them on GOV.UK or with Acas rather than estimating.
What is a COT3?
A COT3 is a legally binding settlement agreement reached through Acas conciliation. It is distinct from a settlement agreement signed with independent legal advice, though both can resolve a dispute without a tribunal hearing.
Can I still go to tribunal if conciliation fails?
Yes. If no agreement is reached, Acas issues an Early Conciliation certificate and you remain free to submit an ET1 claim form and proceed toward a tribunal hearing using that certificate number.