How to Make an Unfair Dismissal Claim: Step-by-Step
Time limits and qualifying periods referenced on this page are correct as of the publication date and are subject to change under the Employment Rights Act 2025 — always check GOV.UK for the current position before relying on a specific deadline.
Introduction
Deciding to bring an unfair dismissal claim is one thing — actually knowing where to start is another. The process involves a mandatory conciliation step before you can even submit a claim, a specific form with its own requirements, and time limits that are genuinely unforgiving if missed.
This guide walks through the practical steps, in order, from checking you have a valid claim through to submitting it and understanding what happens next. If you’re not yet sure whether your situation qualifies as unfair dismissal in the first place, our pillar guide on What Is Unfair Dismissal? A Complete Guide to Your Rights in the UK is worth reading first.
Table of Contents
- Before You Start: Do You Have a Valid Claim?
- Step 1: ACAS Early Conciliation
- Step 2: Completing and Submitting the ET1 Claim Form
- Step 3: What Happens After You Submit Your Claim
- Time Limits You Cannot Afford to Miss
- Do You Need a Solicitor to Make a Claim?
- Contact Us for Expert Employment Law Advice
- Final Thoughts
- Frequently Asked Questions
Before You Start: Do You Have a Valid Claim?
Before working through the process itself, it’s worth checking the basics of your position. In most cases, you need at least two years’ continuous service with your employer to bring an ordinary unfair dismissal claim — if you’re short of that, it doesn’t necessarily rule you out, but it does change what you’ll need to show. Our guide on Unfair Dismissal Under 2 Years: Rules, Exceptions, and the Employment Rights Bill explains the exceptions in detail.
Separately, if your dismissal was connected to a reason like whistleblowing, pregnancy or family leave, or raising a genuine health and safety concern, the normal service requirement may not apply to you at all, and your claim could be significantly stronger as a result. Our guide on Automatic Unfair Dismissal Explained covers which reasons fall into this category.
Step 1: ACAS Early Conciliation
Before you can submit a claim to an Employment Tribunal, you’re generally required to notify ACAS and go through Early Conciliation first — this applies in almost all cases, with only limited exceptions. You do this by contacting ACAS, either online or by phone, and providing basic details of your dispute and your employer.
ACAS will then offer both sides the chance to reach a settlement without the need for a tribunal claim at all, and a genuine proportion of disputes are resolved at this stage. If a settlement isn’t reached — or either side isn’t interested in conciliating — ACAS will issue an Early Conciliation certificate, which includes a certificate number you’ll need in order to complete your tribunal claim form. If you’re weighing up whether resolving things at this stage might suit you better than pursuing a full claim, our guide on What Is a Settlement Agreement in the UK and When Is It Used? explains how that route works.
Early Conciliation also has an important side effect on your time limit, which is covered below — it’s not simply an extra step tacked onto the front of the process, it actively pauses your deadline while it’s ongoing.
Step 2: Completing and Submitting the ET1 Claim Form
Once you have your Early Conciliation certificate number, the next step is completing and submitting form ET1, the official Employment Tribunal claim form, which can be done online through the government’s tribunal service or by post. The form asks for your personal and employment details, your employer’s details, the Early Conciliation certificate number, and a clear explanation of what happened and why you believe your dismissal was unfair.
This last part is worth taking seriously rather than treating as a formality — the explanation you give sets out the basis of your claim from the outset, and it’s far easier to build a strong case on a clearly and accurately framed claim than to try to correct or expand it significantly later on. Setting out dates, the sequence of events, and the specific reason you believe you were dismissed clearly and factually gives your claim the strongest possible foundation.
Step 3: What Happens After You Submit Your Claim
Once your ET1 is accepted, it’s sent to your employer, who then has a set period — usually 28 days — to submit their response using form ET3, explaining whether they dispute the claim and why. From there, the tribunal will typically begin managing the case, which may include issuing directions about evidence and witness statements, and in some cases listing a preliminary hearing before the final hearing itself.
This stage of the process can take considerably longer than people expect given current tribunal workloads — our guide on How Long Does an Employment Tribunal Case Take in the UK? sets out realistic current timelines. It’s also worth knowing that a claim doesn’t have to run all the way to a final hearing to conclude; many cases settle at some point after the ET3 is filed, once both sides have a clearer picture of the strength of the case.
Time Limits You Cannot Afford to Miss
The standard time limit for bringing an unfair dismissal claim is three months less one day from the date your employment ended (Employment Rights Act 2025 will extend this to 6 months starting October 1, 2026). This is one of the strictest deadlines in employment law — tribunals have very limited discretion to allow a late claim, and missing it can mean losing the right to claim at all, regardless of how strong the underlying case is.
Starting Early Conciliation pauses this clock, which is one of the reasons it’s worth contacting ACAS promptly rather than waiting until close to the deadline — the exact mechanics of the pause depend on when in your time limit you start the process, so it’s not simply a case of adding extra weeks on top. This time limit is also under active reform as part of the Employment Rights Act 2025, with an extension to six months expected during 2026 — but until that change actually takes effect, the existing three-month-less-a-day limit still applies, so it’s not safe to assume extra time you don’t yet have.
Do You Need a Solicitor to Make a Claim?
You’re not legally required to have a solicitor to bring a claim, and plenty of people complete the ACAS and ET1 process themselves. Whether that’s the right approach for you depends on how straightforward your claim is and how comfortable you are managing a legal process under time pressure — our guide on Do I Need a Solicitor for an Employment Tribunal? covers this decision in more detail, including the options available if full representation isn’t right for you.
Even where you plan to handle most of the process yourself, a one-off review of your ET1 before you submit it is worth considering, given how much of your claim’s foundation is set at that stage.
Contact Us for Expert Employment Law Advice
Final Thoughts
Making an unfair dismissal claim isn’t complicated in structure — Early Conciliation, then the ET1, then the tribunal process itself — but it is unforgiving of delay, and the quality of your initial claim can shape everything that follows. Starting early, understanding your deadline clearly, and taking care over how your ET1 is framed are the three things most likely to put you in a strong position from the outset.