Unfair Dismissal Claim at Employment Tribunal (2026 Guide)

When Do You Need to File an Unfair Dismissal Claim?

You need to file an ET1 claim for unfair dismissal if your employer dismissed you — or forced you to resign in circumstances that amount to constructive dismissal — and you believe the dismissal was unfair under the Employment Rights Act 1996. Unfair dismissal arises in two main ways:

• Substantive unfairness: Your employer had no potentially fair reason for dismissing you (redundancy, conduct, capability, statutory illegality, or some other substantial reason), or the reason given was not genuine.
• Procedural unfairness: Your employer had a reason but did not follow a fair procedure — for example, failing to give warnings, failing to investigate properly, or denying you the right to be accompanied at a disciplinary hearing.

You can also bring a constructive unfair dismissal claim if your employer’s conduct was so serious that it amounted to a fundamental breach of contract, and you resigned in response to that breach. You must be clear in your ET1 that you resigned in response to the breach — a general resignation will not suffice. Before claiming at the Employment Tribunal you are legally required to notify ACAS under Early Conciliation. This is a mandatory step. ACAS will contact your employer and attempt to broker a settlement. If conciliation does not result in a settlement, ACAS issues an Early Conciliation certificate, which you then use to file your ET1. The certificate also stops the clock on your deadline during the conciliation period.

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What an Unfair Dismissal Claim Involves

An unfair dismissal claim asks the Employment Tribunal to decide two questions:

1. Did the employer have a potentially fair reason for dismissal?
2. If so, did the employer act reasonably in treating that reason as sufficient to dismiss?

The second question is assessed against the band of reasonable responses test: would a reasonable employer, in all the circumstances, have dismissed in the same way? The Tribunal does not substitute its own view for what it would have done — it asks whether the decision fell within the range of reasonable responses open to a reasonable employer. Remedies available:

• Reinstatement: You are returned to your old job as if the dismissal had not occurred.
• Re-engagement: You are given a comparable role with the same employer or an associated employer.
• Compensation: The most common outcome. Compensation consists of a basic award (calculated using your age, length of service, and weekly pay, capped at £751 per week for 2026/27) and a compensatory award (capped at the lower of one year’s gross pay or £123,543 for 2026/27).

Polkey reductions: Even if the Tribunal finds dismissal was unfair, it may reduce your compensation under what is known as the Polkey principle. If your employer could have fairly dismissed you had they followed a proper procedure, the Tribunal may reduce your compensatory award to reflect the likelihood that dismissal would have occurred anyway. A Polkey reduction can be anywhere from a small percentage to 100%, wiping out the compensatory award entirely. Being aware of this is important when assessing the strength and value of your claim. Contributory fault reductions: The Tribunal may also reduce your award if it finds that your own conduct contributed to your dismissal.

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How to Complete Your ET1 for Unfair Dismissal: Step by Step

The ET1 is the claim form you submit to the Employment Tribunal. Completing it accurately and in full is critical. Errors or omissions on your ET1 can limit what you can argue later, as the Tribunal will generally hold you to the case set out in your claim form. Step 1 — Your details and your employer’s details Enter your full name, address, and contact details in Section 1. In Section 2, enter your employer’s full legal name (check your contract or payslip — not just the trading name), the address of the establishment where you worked, and the employer’s phone number. If you are naming multiple respondents (for example, an associated employer or a statutory body), you must add each one. Step 2 — Cases where you are also claiming for something else Tick the unfair dismissal box in Section 8.1. If you also have a wrongful dismissal claim (for unpaid notice pay), a discrimination claim, or an unlawful deduction from wages claim arising from the same facts, include them here. Do not leave related claims out — you cannot easily add them later without Tribunal permission. Step 3 — Employment details In Section 3, confirm your start date, your dismissal date, and whether you were dismissed, made redundant, or resigned (constructive dismissal). Set out your contracted hours, pay, and notice entitlement. These figures feed directly into the calculation of your basic award and any wrongful dismissal element. Step 4 — ACAS Early Conciliation certificate number Every ET1 must include an ACAS Early Conciliation certificate number, or the claim will be rejected. Enter it in Section 2.3. If you are exempt from Early Conciliation, explain why (there are narrow exemptions, such as where the same respondent is already involved in other proceedings before the Tribunal). Step 5 — The details of your claim (Section 8.2) This is the most important part of your ET1. You must set out clearly:

• The date you were dismissed and the reason your employer gave.
• Why you consider that reason to be wrong, fabricated, or insufficient.
• Any procedural failings — failure to investigate, failure to hold a disciplinary hearing, failure to allow an appeal, failure to follow the ACAS Code of Practice on Disciplinary and Grievance Procedures.
• For constructive dismissal: identify the specific conduct of your employer that constituted a fundamental breach of contract, the date you became aware of it, and that your resignation was in direct response to it.
• Any steps you took to challenge the decision internally (appeal, grievance).
• What remedy you are seeking.

Write in plain, factual language. Avoid emotional language. Stick to facts and dates. The Tribunal is interested in what happened and when — not how you felt about it. Be specific about dates, names, and the content of conversations or documents wherever you can. Step 6 — Your losses Set out your financial losses in Section 8.2 or in a separate schedule of loss. Include: loss of earnings from the date of dismissal to the date of the hearing (or to the date you found new work, if you have), loss of statutory rights, and loss of pension contributions if applicable. Attach a schedule of loss if your losses are complex. Step 7 — Review before submission Check every section. Confirm the respondent’s name is legally accurate. Confirm all dates are correct. Confirm your ACAS certificate number matches. Submit the ET1 online through the Employment Tribunals Service portal at http://www.employment-tribunals-service.gov.uk, or by post to the appropriate regional office.

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Key Deadlines for Unfair Dismissal Claims

The time limit for an unfair dismissal claim is three months minus one day from the effective date of termination (EDT). The EDT is usually:
– The date your employment ended (if you were summarily dismissed or dismissed without notice).
– The date notice expired (if you were given or paid in lieu of notice). ACAS Early Conciliation stops the clock. The period during which ACAS is carrying out Early Conciliation is added on to your deadline. When you receive your Early Conciliation certificate, check the dates on it carefully and calculate your adjusted deadline. The two-year qualifying period: To bring an unfair dismissal claim, you must have been continuously employed by the same employer for at least two years at the date of dismissal. There are exceptions for automatically unfair dismissals (for example, dismissals connected to whistleblowing, pregnancy, trade union activity, or the exercise of a statutory right) — in those cases there is no qualifying period. If your dismissal may also involve one of these automatically unfair reasons, include it in your ET1. Late claims: The Employment Tribunal has very limited discretion to extend the three-month deadline. It may do so only if it was not reasonably practicable to present the claim in time, and you presented it within a further reasonable period. This is a narrow test. Do not rely on it. Submit your ET1 as early as possible once you have your ACAS certificate.

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What Happens After You File?

Once your ET1 is accepted, the Employment Tribunal will:

1. Send a copy to the respondent (your employer), who has 28 days to submit an ET3 response form.
2. Issue a case management order setting out the steps both parties must take before the hearing.
3. Schedule a Preliminary Hearing (in some cases) to resolve jurisdictional issues or case management matters.
4. Set a Final Hearing date.

You will usually be required to exchange witness statements and a bundle of documents with the respondent in advance of the hearing. Failing to comply with Tribunal orders can result in your claim being struck out. ACAS may approach both parties again to encourage settlement at any stage before the hearing. A COT3 settlement brokered through ACAS is binding and brings the claim to an end.

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Common Mistakes in Unfair Dismissal Claims

1. Missing the ACAS Early Conciliation step.
You cannot submit an ET1 without first notifying ACAS. Filing without an ACAS certificate will result in rejection. Contact ACAS before doing anything else. 2. Miscalculating the effective date of termination.
If you were paid in lieu of notice or worked your notice period, the EDT is different from the date you were told you were being dismissed. An error here can mean your ET1 is out of time. 3. Failing to meet the two-year qualifying period.
Check your start date against your dismissal date carefully. A gap in service, a change of employer, or a period of self-employment can break continuity. 4. Providing insufficient detail in Section 8.2.
Vague claims such as “I was unfairly dismissed” give the Tribunal nothing to work with. Set out specific facts, dates, and procedural failings. 5. Failing to include all causes of action.
If you also have a discrimination claim or a wrongful dismissal claim, you must include them in the ET1. Omitting a related claim and trying to add it later requires a separate application and is often refused. 6. Ignoring Polkey risk when assessing prospects.
Even a procedurally unfair dismissal may result in low compensation if the Tribunal finds dismissal was inevitable. Overestimating the value of a claim leads to poor settlement decisions. 7. Failing to mitigate your loss.
You are under a duty to take reasonable steps to find new employment after dismissal. Failing to apply for jobs or turning down reasonable offers will reduce your compensatory award.

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Unfair Dismissal and Employment Law

Unfair dismissal is governed primarily by Part X of the Employment Rights Act 1996. The ACAS Code of Practice on Disciplinary and Grievance Procedures (2015) sets out the minimum standards of fair process that employers are expected to follow. The band of reasonable responses test (established in Iceland Frozen Foods Ltd v Jones [1983] ICR 17) remains the central test for assessing procedural and substantive fairness. The Tribunal does not ask what it would have done — it asks whether the employer’s decision fell within the range of decisions a reasonable employer could have made. Polkey v AE Dayton Services Ltd [1987] UKHL 8 establishes the principle that even where a dismissal is unfair due to procedural failings, the Tribunal must consider whether the employer could lawfully have dismissed the employee had a fair procedure been followed. If so, compensation may be reduced accordingly. Contributory fault reductions are governed by section 123(6) of the Employment Rights Act 1996. The qualifying period of two years was introduced by the Unfair Dismissal and Statement of Reasons for Dismissal (Variation of Qualifying Period) Order 2012. What is the time limit for an unfair dismissal claim? A: The standard time limit is three months minus one day from your effective date of termination. The ACAS Early Conciliation period pauses this clock, so your adjusted deadline will be shown on your Early Conciliation certificate. Missing the deadline will almost always result in your claim being rejected.

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Q: Do I need two years of service to bring an unfair dismissal claim? A: Yes, in most cases you need two years of continuous employment with the same employer at the date of dismissal. However, there is no qualifying period for automatically unfair dismissals — which include dismissals connected to pregnancy, whistleblowing, trade union activity, or the exercise of a statutory right.

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Q: What is a Polkey reduction and how could it affect my claim? A: A Polkey reduction is a reduction applied to your compensatory award where the Tribunal finds that, even though the dismissal was procedurally unfair, there was a real chance you would have been dismissed anyway had a fair procedure been followed. The reduction reflects that chance. In some cases a Polkey reduction can be substantial, so it is important to consider this when assessing the value of your claim.

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Q: Do I have to go through ACAS before filing my ET1? A: Yes. Early Conciliation with ACAS is a mandatory pre-claim step in almost all employment tribunal cases. You must notify ACAS before submitting your ET1. The ET1 form requires an ACAS Early Conciliation certificate number and will be rejected without one. ACAS conciliation is free and the process typically takes up to six weeks, though parties can opt out early.

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Q: Can I claim unfair dismissal if I resigned? A: Yes, if you resigned in response to a fundamental breach of contract by your employer, you may have a constructive unfair dismissal claim. You must be able to show that your employer’s conduct was a serious breach that went to the root of the employment contract, that you resigned in direct response to that breach, and that you did not affirm the contract by continuing to work for an unreasonable period after the breach. Constructive dismissal claims are more complex than straightforward dismissal claims and require careful drafting of the ET1.

Related Court Forms & Guides

• Form N260: Statement of Costs — the costs schedule used at summary assessment.
• Form N244: Application Notice — the form for interim applications.
• Start a Money Claim Online (OCMC) — where most civil money claims begin.
• Particulars of Claim — setting out the basis of your claim.
• Civil Court Forms Index — every civil court form guide in one place.

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Frequently asked questions

What is the time limit for an unfair dismissal claim?

The standard time limit is three months minus one day from your effective date of termination. The ACAS Early Conciliation period pauses this clock, so your adjusted deadline will be shown on your Early Conciliation certificate. The Tribunal has only very limited discretion to extend the deadline, so submit your ET1 as early as possible once you have your certificate.

Do I need two years of service to bring an unfair dismissal claim?

In most cases you need two years of continuous employment with the same employer at the date of dismissal. However, there is no qualifying period for automatically unfair dismissals — which include dismissals connected to pregnancy, whistleblowing, trade union activity, or the exercise of a statutory right. If your dismissal may involve one of these reasons, include it in your ET1.

Do I have to go through ACAS before filing my ET1?

Yes. Early Conciliation with ACAS is a mandatory pre-claim step in almost all Employment Tribunal cases. You must notify ACAS before submitting your ET1, and the form requires an ACAS Early Conciliation certificate number — it will be rejected without one.

What is a Polkey reduction and how could it affect my claim?

A Polkey reduction is a reduction applied to your compensatory award where the Tribunal finds that, even though the dismissal was procedurally unfair, there was a real chance you would have been dismissed anyway had a fair procedure been followed. The reduction can be substantial — even up to 100% — so it is important to weigh this when assessing the value of your claim.

Can I claim unfair dismissal if I resigned?

Yes, if your employer’s conduct was so serious that it amounted to a fundamental breach of contract and you resigned in direct response to that breach — this is constructive dismissal. You must make clear in your ET1 that you resigned in response to the breach; a general resignation will not suffice.

What is the most important part of the ET1 to get right?

Section 8.2 — the details of your claim. Set out the dismissal date, the reason given, why that reason is wrong or insufficient, any procedural failings, and the remedy you seek, in plain, dated, factual language. The Tribunal will generally hold you to the case set out in your claim form, so vague claims and omitted causes of action can limit what you argue later. Related guides: Ask Chris about your employment claim · All civil court forms