Conciliation is a process in which an impartial third party — in the UK employment context, almost always a conciliator from Acas — helps an employer and an employee settle a dispute and avoid, or end, an employment tribunal claim. Its most important form is Acas early conciliation, a mandatory step that nearly everyone must go through before they can lodge a tribunal claim. Conciliation is free, confidential and voluntary in outcome: the conciliator cannot impose a settlement, but they can carry offers between the parties, explain the realities of litigation, and help both sides reach a binding agreement that keeps the dispute out of the tribunal.
This guide explains what conciliation is, how the compulsory early conciliation process works, the recently extended 12-week conciliation period and the “stop the clock” effect on tribunal time limits, what a binding COT3 settlement is and how it differs from a settlement agreement, and how conciliation compares with mediation. It is written for UK employers and employees who want to understand this crucial gateway to — and often away from — the tribunal.
In short: Acas early conciliation is a free, confidential step that must be attempted before most employment tribunal claims. You notify Acas, a conciliator tries to broker a settlement, and the strict tribunal time limit is paused (“stop the clock”) while it runs. Since 1 December 2025 the conciliation period can last up to 12 weeks (previously six). A settlement is recorded in a binding COT3; if no settlement is reached, Acas issues a certificate that lets the claimant proceed to tribunal.
Key takeaways
- Early conciliation is compulsory before most tribunal claims — you must notify Acas and obtain a certificate first.
- The conciliation period now lasts up to 12 weeks (extended from six on 1 December 2025), and the tribunal time limit is paused while it runs.
- It is free, confidential and voluntary — neither side has to settle, and what is discussed cannot be used at a tribunal.
- A settlement is recorded in a COT3, which is legally binding and — unlike a settlement agreement — needs no independent legal advice.
- If no settlement is reached, Acas issues a certificate with a reference number the claimant needs to lodge an employment tribunal claim.
In this guide
- What conciliation is
- Early conciliation: the mandatory step
- How the process works
- The 12-week period and stop the clock
- COT3 settlements
- Conciliation during proceedings
- Conciliation, mediation and settlement
- Should you engage?
- Time-limit changes ahead
- Worked example
- Common mistakes
- The conciliator role
- What a settlement covers
- Preparing for conciliation
- What we see in practice
- How Hayhills can help
- FAQs
What conciliation is
Conciliation is a form of alternative dispute resolution in which an impartial conciliator helps parties to a dispute reach a settlement. In UK employment law it is delivered by Acas (the Advisory, Conciliation and Arbitration Service), a public body whose conciliators are experienced, neutral and free to use. The conciliator does not decide who is right, does not give either side legal advice, and cannot force a settlement. What they do is act as a trusted go-between: relaying offers, testing each side’s expectations against the likely outcome and cost of litigation, and helping the parties find terms they can both live with.
Conciliation matters because the alternative — fighting a claim to a full tribunal hearing — is slow, stressful and expensive for both sides. Most employment disputes settle rather than going all the way to a hearing, and Acas conciliation is the main channel through which that happens. Understanding how it works, and using it well, is therefore one of the most valuable things either an employer or an employee can do when a dispute arises.
Early conciliation: the mandatory step
For most potential tribunal claims, conciliation is not optional at the start. Since 2014, a prospective claimant must notify Acas before they can lodge a tribunal claim — this is “early conciliation”. The claimant contacts Acas (online or by phone) with basic details of the dispute. Acas then offers conciliation to try to settle the matter before any claim is issued. The respondent employer is not obliged to take part, and the claimant is not obliged to settle, but the step of notifying Acas is compulsory: without it, the tribunal will generally reject the claim.
The purpose is to give every dispute a genuine chance to resolve without litigation. Many do: a conciliator can often bridge a gap that the parties, talking directly, cannot. Even where settlement is not reached, the process gives both sides an early, realistic sense of the other’s position and the strength of the claim, which can shape what happens next.
How the early conciliation process works
The mechanics are straightforward, and deliberately so:
- Notify Acas. The prospective claimant completes the early conciliation notification with their details and the employer’s. This must be done within the tribunal time limit.
- Allocation to a conciliator. Acas contacts the parties and, if both are willing, a conciliator explores whether settlement is possible.
- Shuttle negotiation. The conciliator speaks separately to each side, carrying offers and counter-offers and helping each assess the risks and costs of proceeding.
- Outcome. If the parties agree terms, the settlement is recorded in a binding COT3 and the dispute ends. If not — or if a party declines to engage — Acas issues an early conciliation certificate.
That certificate carries a unique reference number, which the claimant must quote to lodge a tribunal claim. No certificate, no claim: it is the procedural key that unlocks the tribunal. Importantly, taking part in conciliation does not commit either side to anything — a claimant who does not settle keeps the full right to bring their claim, and an employer who explores settlement is not admitting liability.
The 12-week period and “stop the clock”
Two features make the timing of early conciliation critical. First, the conciliation period: from 1 December 2025 it lasts up to 12 weeks (extended from the previous six), giving the parties more time to reach a deal. Second, the “stop the clock” rule: the strict tribunal time limit — usually three months less one day from the act complained of — is paused while early conciliation is under way, and effectively extended by the time it took.
| Stage | What happens | Effect on the time limit |
|---|---|---|
| Day A | Claimant notifies Acas | The clock stops |
| Conciliation | Up to 12 weeks of conciliation | Limitation period paused throughout |
| Day B | Acas issues the certificate | The clock restarts |
| After Day B | Claimant may lodge the ET1 | At least one month to do so if little time remained |
The interaction of these rules is technical, and miscalculating it is one of the most common ways claimants lose the right to bring an otherwise good claim. As a safety net, where the time remaining after Day B is short, the claimant generally has at least a month from Day B to lodge the claim. But the safest approach is never to leave conciliation to the last minute, and to treat the deadline arithmetic with great care.
COT3 settlements
If conciliation produces a deal, the terms are recorded by the Acas conciliator in a document called a COT3. A COT3 is a legally binding settlement: once both parties agree, the claim (or potential claim) is settled on those terms and cannot be pursued. It is typically used to record a payment, an agreed reference, confidentiality terms, and a waiver of the relevant claims.
The COT3 has a notable advantage over the alternative route of a settlement agreement. To validly waive statutory employment claims through a settlement agreement, the employee must receive independent legal advice and the agreement must meet strict statutory conditions. A COT3 reached through Acas needs no independent legal advice to be binding, because the involvement of the Acas conciliator provides the safeguard the law requires. That makes a COT3 quicker and cheaper to conclude — though each party should still understand exactly what they are agreeing, because a COT3 is just as final.
Conciliation during tribunal proceedings
Conciliation does not end if early conciliation fails and a claim is lodged. Acas continues to offer conciliation right through the life of a tribunal case, and many claims that were not settled before issue are settled later — sometimes shortly before the hearing, as the cost and risk of proceeding become starker for both sides. The same conciliator-led, confidential, voluntary approach applies, and any settlement is again recorded in a binding COT3.
This continuing availability is why a high proportion of tribunal claims never reach a final hearing. For both parties it is worth keeping the conciliation door open throughout: positions that seem irreconcilable at the outset often soften as the evidence, the costs and the uncertainty of a hearing come into focus.
Conciliation, mediation and settlement agreements compared
These three routes are easily confused but do different jobs.
| Feature | Acas conciliation | Workplace mediation | Settlement agreement |
|---|---|---|---|
| Focus | Settling a tribunal claim | Repairing a working relationship | Recording agreed terms (often an exit) |
| Who runs it | An Acas conciliator | A neutral mediator | The parties and their advisers |
| Independent legal advice? | Not required (COT3) | Not applicable | Required to waive statutory claims |
| Binding outcome | COT3 (binding) | Usually not binding by itself | Binding contract |
| Cost | Free | Low | Legal costs involved |
In practice they often connect. A dispute might begin with workplace mediation aimed at the relationship; if that fails and a claim looms, Acas conciliation tries to settle the claim; and the terms might be documented either in a COT3 or, in some situations, a settlement agreement. Knowing which tool fits the stage of the dispute saves time and money.
Should you engage with conciliation?
For most parties, the answer is yes — engaging does not mean conceding. For an employer, conciliation is a low-risk way to test whether a dispute can be resolved cheaply and confidentially before the costs and management time of litigation mount up, and before any reputational exposure of a public hearing. For an employee, it is a free, no-obligation chance to secure a fair outcome quickly, without the stress and delay of a full hearing. Neither side admits anything by taking part, and either can walk away and let the tribunal process run.
That said, engagement should be informed. Going into conciliation with a realistic view of the strengths and weaknesses of the case, the likely range of outcomes at a tribunal, and a clear sense of what a good settlement looks like makes the process far more productive. This is exactly where advice before and during conciliation earns its keep — not to obstruct settlement, but to make sure any deal reached is a sensible one.
Time-limit changes on the horizon
The conciliation landscape is shifting. The extension of the conciliation period to 12 weeks took effect on 1 December 2025, and the Government has said it will review in October 2026 whether the longer period should stay. Separately, reform is expected to extend the basic tribunal time limit from three months to six months, with October 2026 cited as the likely point — a significant change that would affect when conciliation must be started and when claims must be brought. Because these timing rules are technical and in flux, anyone dealing with a potential claim should check the current position carefully and, where the stakes are high, take advice rather than rely on a remembered deadline. Always confirm the latest rules at Acas and GOV.UK.
Worked example
Scenario. An employee believes she was unfairly dismissed. The dismissal took effect on 1 March, so her tribunal deadline is ordinarily three months less a day — around 31 May. On 15 May she notifies Acas for early conciliation.
How the clock works. Notifying Acas on 15 May (Day A) stops the clock with about 16 days left on her limit. Conciliation runs for several weeks. When Acas issues the certificate (Day B), the clock restarts. Because so little time remained, she benefits from the safety-net rule giving her at least one month from Day B to lodge her claim — so she is not caught out by the days that had already elapsed.
The outcome. During conciliation the employer, weighing the cost and risk of a hearing, offers a settlement. The conciliator brokers terms — a payment plus an agreed reference — recorded in a binding COT3. The claim is resolved in weeks, confidentially, with no hearing, and the employee did not need to pay for independent legal advice to make the settlement binding.
Common mistakes to avoid
- Leaving early conciliation too late. Notify Acas in good time — the stop-the-clock arithmetic is unforgiving if you cut it fine.
- Treating engagement as concession. Taking part admits nothing and you can still proceed to tribunal.
- Miscalculating the deadline. The Day A / Day B rules are technical; an error can lose an otherwise good claim.
- Signing a COT3 without understanding it. A COT3 is binding and final — be clear what claims you are giving up.
- Refusing to engage at all. Declining conciliation outright forfeits a free, low-risk chance to settle.
- Forgetting conciliation stays open. Even after a claim is lodged, Acas can still help you settle — use it.
What we see in practice
Conciliation is not optional paperwork — for most employment disputes it is a legal gateway. Before bringing the majority of tribunal claims an employee must first notify Acas and go through early conciliation, a mandatory step under section 18A of the Employment Tribunals Act 1996. Acas issues an early conciliation certificate, and crucially the tribunal time limit is paused while conciliation runs, which is where claimants most often miscount their deadline.
If terms are agreed, the settlement is recorded on a COT3. We like the COT3 because it is binding and, unlike a standard settlement agreement, it does not require the employee to take independent legal advice to be valid — which makes it quicker and cheaper to conclude. The trade-off is that its wording is brief, so we always check the scope of what is being waived before anyone signs, because a COT3 can settle far more than the single dispute in front of you.
How Hayhills can help
Hayhills Legal Advisory helps UK employers and employees prepare for and get the most out of Acas conciliation — assessing the merits and likely value of a claim, planning a negotiating position, and making sure any COT3 settlement is sensible and clearly understood before it is signed. As a non-reserved legal advisory service we focus on strategy, risk assessment and support through the conciliation process; where a matter proceeds to a contested tribunal hearing — a reserved activity — we introduce a trusted regulated professional to conduct the litigation. Related reading: our guides to employment tribunals, settlement agreements and workplace mediation.
The role of the Acas conciliator
It helps to be clear about what an Acas conciliator does and does not do, because misunderstanding the role leads people to mistrust a process that is actually on their side. The conciliator is impartial: they do not represent either party and have no interest in the outcome beyond helping the parties reach one they both accept. They will not tell a claimant their claim is worth a particular sum, nor advise an employer how to defend it — that is the job of each side’s own adviser. What the conciliator brings is experience of how disputes like this typically resolve, and the ability to move offers back and forth confidentially without either side losing face.
Because conversations with the conciliator are confidential and without prejudice, each party can be candid about what they would accept without that information being passed to the other side or used at a hearing. A claimant can indicate a realistic bottom line, and an employer a realistic ceiling, and the conciliator can work in the space between them. This confidentiality is the engine of conciliation: it lets people explore settlement honestly in a way that open, adversarial correspondence never allows. The conciliator’s neutrality and discretion are precisely why the process settles so many disputes that the parties could not resolve alone.
What a conciliated settlement covers
A settlement reached through conciliation and recorded in a COT3 can deal with far more than a simple payment. Common terms include a financial sum in settlement of the claims, an agreed reference for the departing employee, confidentiality about the terms (subject to the legal limits on silencing disclosures of harassment or discrimination), and a clear waiver defining exactly which claims are being settled. The parties can be creative: outcomes might include an agreed form of words about the reason for leaving, the return of company property, or the treatment of shares or benefits.
Tax treatment matters too. Genuine termination payments can often be paid free of tax up to a threshold of £30,000, with sums above that and certain contractual payments taxable in the normal way — so how a settlement is structured and described affects what each side actually receives or pays. Because a COT3 is final, both parties should understand the scope of the waiver and the tax position before agreeing. A well-structured settlement resolves not just the immediate claim but the loose ends that could otherwise cause friction later.
Preparing for conciliation
Conciliation rewards preparation. Before engaging, each side benefits from an honest assessment of the merits of the claim, the likely range of outcomes if it went to a hearing, and the costs and time of getting there. A claimant who knows what their claim is realistically worth, and an employer who understands its exposure, can negotiate purposefully rather than guessing. It also helps to decide in advance on a target outcome and a walk-away point, so that decisions in the moment are anchored to a considered position rather than made under pressure.
Practical readiness matters as well: gathering the key facts and documents, being clear about non-financial priorities (such as a reference or an agreed narrative), and understanding the deadline arithmetic so conciliation is not derailed by a looming time limit. None of this means approaching conciliation as a battle — the aim is a sensible resolution — but a party that arrives informed and organised consistently achieves better outcomes than one that arrives hoping for the best. This preparatory thinking is where advice adds the most value, well before any settlement is signed.
Why early conciliation exists
Early conciliation was introduced to take pressure off the tribunal system and, just as importantly, to give disputes a real chance of resolving before they harden into litigation. Tribunal hearings are costly to run and stressful to attend, and a great many employment disputes are, at heart, capable of sensible compromise. By requiring everyone to pause and at least notify Acas before issuing a claim, the system builds in a moment for settlement that might otherwise be skipped in the rush to lodge a claim before a deadline.
The approach has been broadly successful: a large share of notifications lead to settlement or to the dispute being resolved without a hearing, and the conciliation route is now a settled, well-understood part of the employment landscape. The 2025 extension of the conciliation period to twelve weeks reflects confidence in the model — giving parties more breathing space to reach agreement — while the planned review keeps it under sensible scrutiny. For employers and employees alike, the practical message is that conciliation is not a hurdle to be cleared on the way to a hearing, but often the most efficient way to resolve the dispute altogether.
The bottom line
Whether you are an employer facing a potential claim or an employee considering one, conciliation deserves to be taken seriously rather than treated as a box-ticking formality. It is free, confidential, carries no obligation to settle, and frequently produces a faster, cheaper and less stressful outcome than a tribunal ever could. Engaging constructively — informed by a realistic view of the case and clear about what a good result looks like — gives both sides the best chance of resolving the dispute on acceptable terms and moving on.
If conciliation does not produce a settlement, nothing is lost: the claimant simply takes the Acas certificate and proceeds to the tribunal with their case intact. That is the reassurance at the heart of the process — you can try to settle without giving anything up, and only a genuinely acceptable agreement will end the dispute. Used in that spirit, conciliation is one of the most useful tools in UK employment law, and one that too many parties approach with unnecessary suspicion.
This article is for general information only and does not constitute legal or accountancy advice. Hayhills Limited, trading as Hayhills Legal Advisory, provides non-reserved legal advisory services. Always check current requirements at Acas and GOV.UK.
Frequently asked questions
What is Acas early conciliation?
Acas early conciliation is a free, confidential step that most people must take before lodging an employment tribunal claim. You notify Acas, and a conciliator tries to help the parties settle the dispute without litigation. Notifying Acas is compulsory; settling is voluntary.
Is conciliation compulsory?
Notifying Acas for early conciliation is compulsory before most tribunal claims — without an Acas certificate the tribunal will usually reject the claim. However, neither party is obliged to settle, and the employer is not obliged to take part in the conciliation itself.
How long does early conciliation last?
Since 1 December 2025 the early conciliation period can last up to 12 weeks, extended from the previous six weeks. The strict tribunal time limit is paused while conciliation is under way, under the stop-the-clock rule.
What is the stop-the-clock rule?
When you notify Acas (Day A), the tribunal time limit — usually three months less a day — is paused. When Acas issues the certificate (Day B), the clock restarts. If little time remained, you generally have at least one month from Day B to lodge your claim.
What is a COT3 agreement?
A COT3 is the document an Acas conciliator uses to record a settlement reached through conciliation. It is legally binding and ends the claim on the agreed terms. Unlike a settlement agreement, a COT3 does not require the employee to take independent legal advice.
What is the difference between a COT3 and a settlement agreement?
Both settle claims, but a settlement agreement requires the employee to receive independent legal advice and meet strict statutory conditions to waive claims. A COT3, reached via Acas, needs no independent advice because the conciliator’s involvement provides the safeguard.
Does conciliation continue after I lodge a claim?
Yes. Acas continues to offer conciliation throughout the tribunal process, and many claims settle later — sometimes shortly before the hearing. Any settlement is again recorded in a binding COT3. It is worth keeping the conciliation option open throughout.
Is conciliation the same as mediation?
No. Acas conciliation is focused on settling a tribunal claim, led by an Acas conciliator and free of charge. Workplace mediation focuses on repairing a working relationship, led by a neutral mediator, and its outcome is usually not legally binding by itself.
Does it cost anything to use Acas conciliation?
No. Acas early conciliation and continuing conciliation are free to both parties. There may be costs in taking advice on the merits of a claim or the terms of a settlement, but the conciliation service itself carries no charge.
Will the tribunal time limit change?
Reform is expected to extend the basic tribunal time limit from three months to six months, with October 2026 cited as the likely point, and the 12-week conciliation period is also due to be reviewed then. Because these rules are technical and changing, always check the current position.