Resolving Workplace Disputes with Acas: Full UK Guide

At a glance

• Mandatory first step: early conciliation with Acas is required before most employment tribunal claims in England, Scotland and Wales — Employment Tribunals Act 1996, s.18A.
• Conciliation window: 12 weeks from the date you first notify Acas, increased from 6 weeks with effect from 1 December 2025, with no option to extend it further.
• Tribunal time limit: generally three months less one day from the relevant date (dismissal, act complained of, deduction, etc.), extended by the "stop the clock" rule while conciliation is ongoing — Employment Rights Act 1996, s.207B.
• Code of Practice adjustment: a tribunal can increase or reduce certain awards by up to 25% where a party unreasonably failed to follow the Acas Code of Practice on Disciplinary and Grievance Procedures — TULRCA 1992, s.207A.
• COT3: the legally binding settlement recorded through Acas conciliation, and one of the recognised ways to validly settle tribunal claims without a separate settlement agreement — Employment Rights Act 1996, s.203.
• Free to use: Acas conciliation, the helpline and its published guidance carry no charge. The separate Acas arbitration scheme is voluntary and only available for unfair dismissal and flexible working disputes where both sides agree.

What Acas does

Acas — the Advisory, Conciliation and Arbitration Service — is a publicly funded, independent statutory body that supports better working relationships in England, Scotland and Wales. It is not a regulator and it does not take sides. Its job is to help employers and employees find practical ways through disagreements, from pay disputes and discrimination complaints to dismissal and redundancy issues.

Acas performs several distinct functions. It runs a telephone helpline and publishes extensive guidance on employment matters. It provides early conciliation, which is a mandatory step before most tribunal claims can be lodged. It also offers voluntary (post-claim) conciliation for disputes that have already reached the tribunal. And it operates a separate, opt-in arbitration scheme for certain claim types.

Acas also issues statutory Codes of Practice — most importantly the Code on Disciplinary and Grievance Procedures — which tribunals must take into account when relevant, and which can move the size of a compensation award.

Early conciliation: the mandatory first step

Before a person can normally present most types of tribunal claim, they must notify Acas and be given "prescribed information" about the dispute — either online or by phone. This requirement comes from section 18A of the Employment Tribunals Act 1996. A conciliation officer is then assigned, and a fixed conciliation period begins during which they will try to help the parties reach a settlement.

That period is currently 12 weeks. It was increased from the previous 6-week period by regulations that came into force on 1 December 2025, and — unlike the earlier rules, which allowed a short agreed extension — there is now no mechanism to extend the 12 weeks further. If a settlement is reached, or if the conciliator concludes early on that no agreement is possible, Acas can issue the early conciliation certificate before the 12 weeks are up. Without that certificate (or a recognised exemption), a tribunal claim cannot normally proceed.

A small number of claim types are exempted from the requirement by regulations made under section 18A, and there are also situations — for example where another party has already notified Acas about the same matter — where a person does not need to make a fresh notification themselves.

The tribunal time limit and the "stop the clock" rule

Most employment tribunal claims must be brought within a strict time limit — generally three months less one day from the relevant date (for example, the effective date of termination for unfair dismissal, or the date of the act complained of for discrimination). GOV.UK confirms claimants must normally get an Acas early conciliation certificate, or a valid reason for not having one, before the tribunal will accept a claim.

Because early conciliation itself takes time, the law prevents the conciliation window from eating into that time limit. Under section 207B of the Employment Rights Act 1996, the period between "Day A" (the day you notify Acas) and "Day B" (the day you receive, or are treated as receiving, your certificate) is not counted when working out whether your time limit has expired. There is also a backstop: if your deadline would otherwise fall during conciliation, or within one month after Day B, it is instead extended to one month after Day B.

This extension is a safety net, not a substitute for knowing your actual deadline. It is easy to miscalculate, and a late claim can be struck out, so working out the specific date early — rather than assuming Acas contact automatically "resets the clock" — is the safer approach.

The Acas Code of Practice and the up-to-25% adjustment

The Acas Code of Practice on Disciplinary and Grievance Procedures was brought into legal effect by statutory order in 2009, issued by Acas under its statutory Code-making power. It sets out the minimum fair process expected for handling conduct and performance issues, and individual grievances — it does not apply to redundancy dismissals or to the non-renewal of a fixed-term contract.

A failure to follow the Code does not, by itself, make a claim succeed or fail. But under section 207A of the Trade Union and Labour Relations (Consolidation) Act 1992, where a tribunal finds that a party unreasonably failed to comply with the Code in a matter it applies to, it may — if it considers it just and equitable — adjust certain awards by up to 25%. This can work against an employer (increasing compensation for skipping proper process) or against an employee (reducing an award where the employee unreasonably failed to engage with the process, for example by refusing to attend a disciplinary or grievance hearing without good reason).

COT3 settlements

If early conciliation produces an agreement, the terms are typically recorded in a COT3 — the settlement document used by Acas. Once both parties sign it, a COT3 is legally binding and normally prevents the claims it covers from being pursued again.

This works as a legal matter because of an exception built into employment law's general rule against "contracting out": ordinarily, an agreement that tries to stop someone bringing a tribunal claim is void. Section 203 of the Employment Rights Act 1996 carves out settlements reached through Acas conciliation as one of the valid ways around that rule — which is why a COT3 does not need the same independent-legal-advice conditions that a standalone settlement agreement requires. That makes it faster to arrange, but it also means reading it carefully matters: signing gives up the right to bring the specific claims covered, so understanding exactly what is (and is not) being waived, and whether the terms reflect the strength of your case, is worth doing before signing.

Acas arbitration: a voluntary alternative to tribunal

Separately from conciliation, Acas operates an arbitration scheme under a statutory order that came into force in 2004. Under this scheme, an independent arbitrator hears both sides privately and issues a binding decision, similar to a judge — but the process is intended to be more informal, confidential and quicker than a tribunal hearing.

Crucially, arbitration under this scheme is only available for unfair dismissal claims and, under a related order, flexible working disputes, and it requires both employer and employee to agree in writing to use it instead of the tribunal. It is used far less often than conciliation, but it can suit disputes where both sides want a fast, private and final resolution.

Practical steps to resolving a dispute through Acas

1. Try to resolve it internally first. Before contacting Acas, most situations benefit from a proper internal conversation — raise the concern with a line manager, HR, or the employee directly if you are the employer. Follow any grievance or disciplinary procedure in the contract or staff handbook; tribunals expect parties to have genuinely tried to sort things out in-house, and this is also where the Acas Code of Practice becomes relevant.
2. Contact Acas for early conciliation. If internal steps have not worked and a tribunal claim is being considered, notify Acas through the early conciliation form or by phone. A conciliator is assigned, and the 12-week conciliation period begins.
3. Engage properly with the conciliator. They act as a neutral go-between — they do not decide who is right, but they relay positions, test the strength of arguments and suggest realistic outcomes. Being candid about what you want, what you would accept, and what evidence you have tends to make the process more productive, and it is protected from being used as evidence later.
4. Consider a COT3 settlement. If both parties reach agreement, the terms are usually recorded in a COT3. Read it carefully — signing typically means giving up the right to bring the specific claims it covers.
5. Move to tribunal or arbitration if needed. If conciliation does not produce a deal, Acas issues an early conciliation certificate, which is required to lodge most tribunal claims. In unfair dismissal or flexible working disputes, the Acas arbitration scheme is an alternative to tribunal — but only if both sides agree to use it.

A note on the wider law

Employment law in this area continues to change. The Employment Rights Act 2025 introduces a range of further reforms, but not all of them are in force yet, and they are being phased in over 2026 and 2027 under separate commencement regulations. For example, GOV.UK confirms the qualifying period to bring an ordinary unfair dismissal claim is still generally 2 years' service, with a reduction to 6 months' service due to commence from 1 January 2027 — it is not yet in force. None of this changes the mandatory Acas early conciliation process, the current 12-week conciliation window, or the time limits described above, which reflect the law as it stands today.

This guide provides general information about resolving workplace disputes with Acas in England and Wales. It is not legal advice and is not a substitute for advice tailored to your specific circumstances. The law described was accurate as at August 2026 and is subject to change — always check GOV.UK and legislation.gov.uk for the most current position, or speak to an adviser about your situation.

Last reviewed: August 2026 by a non-practising solicitor · Next review due: August 2027 or on legislative change.