The ET1 form is often the moment a workplace dispute stops feeling like a grievance and starts feeling like a legal case. After weeks of frustration — a dismissal that felt wrong, wages that never arrived, treatment that crossed a line — you finally reach the point where you have to formally set out what happened.
Then you open the form.
Fifteen pages of official language can make anyone hesitate. Most employees worry they’ll phrase something badly or miss a detail that weakens their case.
Here’s the part worth knowing first: employment tribunals don’t expect a perfectly drafted legal document. What judges want is a clear, factual account of what happened and why you believe your employer broke the law. Plain language and a logical timeline outperform legal jargon every time.
The ET1 is the official document that starts an employment tribunal claim in England, Scotland, or Wales. This guide covers every section, the deadlines — including two significant 2026 rule changes — the ACAS requirements, and the mistakes that cause claims to be returned before they’re ever read.
What Is an ET1 Form?
The ET1 is the official application for starting a claim with a UK Employment Tribunal. It tells the tribunal who you are, who your employer is, what happened, and which employment rights you believe were breached.
As GOV.UK’s ET1 form page confirms, the form is available as a PDF download or through the online claim service — and where multiple employees are making claims from the same circumstances, a separate ET1A form handles group applications.
Once the tribunal accepts the ET1, it forwards the claim to the employer, who must respond using an ET3 form within 28 days.
Common claims made through ET1:
- Unfair dismissal
- Workplace discrimination
- Unpaid wages or unlawful deductions
- Breach of contract
- Redundancy disputes
- Holiday pay underpayments
When Must You Submit the ET1?
Tribunal claims carry strict deadlines — and 2026 brings two changes that every claimant needs to know.
| Claim Type | Current Deadline |
|---|---|
| Unfair dismissal | 3 months minus 1 day after dismissal |
| Discrimination | 3 months after the discriminatory act |
| Unlawful wage deduction | 3 months after the deduction |
Missing a deadline means the claim is usually rejected. Exceptional circumstances occasionally allow late submissions, but tribunals grant these sparingly.
Two important 2026 updates:
First, from 1 December 2025, the ACAS Early Conciliation period doubled from six weeks to twelve weeks. As Farrer & Co’s analysis confirms, this applies to all conciliation notifications made on or after that date — claims already in progress before December 2025 continue under the old six-week rule.
Second, under the Employment Rights Act 2025, most tribunal time limits are expected to extend from three months to six months in October 2026. Until that date, three months still applies. As Capital Law’s employment briefing notes, the combination of a 12-week conciliation period and a six-month primary limit will eventually give claimants up to ten months from the triggering event — but that’s not the current position.
The ACAS “Stop the Clock” Rule: Updated for 2026
Before filing an ET1, you must contact ACAS to start Early Conciliation. This step is mandatory for most claims.
As ACAS confirms on its time limits page, notifying ACAS within your primary deadline pauses the clock. The entire conciliation period — now up to 12 weeks — doesn’t count toward your three-month window. Once ACAS issues the Early Conciliation certificate, the clock restarts. You then have whichever is later: one month from the certificate date, or the remaining days from your original three-month window.
| Event | Example Date |
|---|---|
| Dismissal occurs | 1 March |
| ACAS conciliation starts | 20 March |
| ACAS conciliation ends | 15 June (up to 12 weeks) |
| Clock restarts | 15 June |
Because the arithmetic can get complicated — particularly where conciliation runs close to the original deadline — the Tribunal Claims Solicitors’ free time limits calculator works through the exact dates for any dismissal scenario.
How to Complete the ET1: Section by Section
Section 1: Claimant details
Full name, address, email, phone number, and date of birth. The tribunal uses these details for every subsequent communication. An address error sends letters to the wrong place — check carefully before submitting.
Section 2: Respondent (employer) details
The legal name of the company, its address, and contact details. As Protect Advice’s ET1 guide confirms, the respondent’s name must match the name on your ACAS conciliation certificate exactly. If in doubt, verify the registered company name on Companies House before submitting. Section 2.3 specifically requests the ACAS Early Conciliation certificate number — copy it character by character. A single error here is the most common validation failure.
Section 3: Employment details
Job title, start date, end date, salary, and notice period. These figures help the tribunal calculate potential compensation if the claim succeeds.
Example: “I was employed as a customer service supervisor from April 2021 until my dismissal on 12 February 2025. My annual salary was £29,000.”
Telling Your Story to the Tribunal
Section 8 — “Details of the Claim” — is where the case actually begins. As Citizens Advice’s employment tribunal guidance confirms, this is the first document the tribunal reads — number your paragraphs, keep to chronological order, and make specific parts easy to find and reference.
No legal language required. A clear structure works best:
- Background — your role and working conditions
- Key events — what happened and when, in date order
- Outcome — dismissal, discrimination, withheld pay, or another result
- Why it was unlawful — your belief that the employer broke employment law
Example: “On 15 January 2025 I reported repeated safety concerns to my manager. Two weeks later I was dismissed without warning. I believe the dismissal was retaliatory and therefore unfair.”
Judges read dozens of ET1 forms. The ones that read clearly move faster.
Particulars of Claim for Complex Cases
Where Section 8 isn’t large enough, write “See attached Particulars of Claim” in the box and attach a separate document. As GOV.UK’s tribunal forms collection confirms, uploaded documents should be in Word, PDF, or RTF format.
A Particulars document typically covers: background of employment, chronological events, the legal claims being made, and a description of losses or harm. For straightforward unfair dismissal claims, writing directly in Section 8 is usually enough.
How to Submit the ET1 Online
- Complete ACAS Early Conciliation and receive your certificate
- Open the online ET1 claim service
- Fill in all required sections
- Upload supporting documents — contracts, payslips, emails, screenshots
- Submit and save the confirmation reference
GOV.UK’s employment tribunal forms collection holds all current versions — ET1 (individual claims), ET1A (group claims), and ET3 (employer response) — all updated March 2026.
What Happens After Submission
Submitting the form doesn’t automatically mean the case proceeds. The tribunal runs a validation check first, confirming the ACAS certificate number is valid, the claim landed within the deadline, employer details are identifiable, and the claim contains enough information to progress.
As Citizens Advice confirms, if you want to change the ET1 after submission, write to the tribunal and ask for an amendment. Small corrections — a name spelling, a date — are usually accepted. Bigger changes, like adding a new legal claim, need to be requested early. The longer you wait, the less likely the tribunal is to allow it.
Employer response: Once the ET1 passes validation, the tribunal sends it to the employer. The employer must respond using an ET3 form within 28 days. Failure to respond can result in a default judgment or the case proceeding without their defence.
Digital Evidence in 2026
Tribunals are tightening how they handle digital evidence. WhatsApp messages, Slack conversations, emails, and text screenshots cited in an ET1 may not be enough on their own — tribunals increasingly request original screenshots with visible timestamps and full conversation context rather than a claimant’s summary.
Save originals from the moment a workplace dispute develops. Screenshots taken months later are harder to authenticate than those captured at the time.
If Your Employer Has Closed or Gone Insolvent
Claims can still proceed in certain circumstances — through the Redundancy Payments Service, by naming administrators or insolvency practitioners, or by including additional responsible parties. As Citizens Advice’s tribunal guidance notes, this area is legally complex and professional advice is worth seeking before proceeding.
Common Mistakes That Delay Claims
Missing the deadline — the most damaging error. There is very limited discretion to extend once the window closes.
Wrong ACAS certificate number — a single character error fails validation. Copy it directly from the certificate document.
Incorrect company name — use the registered name from Companies House, not a trading name or the name on your payslip if they differ.
Vague claim descriptions — “I was treated unfairly” without dates, events, or reasons gives the tribunal nothing to assess.
Emotional rather than factual writing — the frustration is understandable, but timelines and specific facts move cases forward.
ET1 Quick Checklist
- ✔ ACAS Early Conciliation completed and certificate received
- ✔ Certificate number copied accurately into Section 2.3
- ✔ Employer’s registered legal name verified on Companies House
- ✔ Claim timeline written clearly with dates and numbered paragraphs
- ✔ Evidence prepared and saved in original format
- ✔ Submission deadline confirmed — not estimated from memory
FAQs
Q. What exactly is an ET1 form?
An ET1 form is how you officially start a claim with a UK employment tribunal. Think of it as the paper (or online form) that tells the tribunal: “Here’s who I am, who my employer is, and what went wrong.” Common claims include unfair dismissal, discrimination, unpaid wages, or breach of contract. You can download a PDF or submit it directly on the GOV.UK ET1 page.
Q. How do I actually submit an ET1 online?
Submitting online is straightforward once you’ve completed ACAS Early Conciliation. You’ll need the certificate number from ACAS before anything else. Then, fill out the ET1 form on the tribunal website and attach your supporting documents — contracts, payslips, emails, or screenshots. Doing it online is faster than sending paper, and the system usually catches small errors before submission.
Q. What happens after I hit “submit”?
Once your ET1 reaches the tribunal, they check everything carefully. They confirm your ACAS certificate number is correct and that you submitted on time. After that, the employer gets a copy and has 28 days to respond using an ET3 form. You’ll receive their response too, so you know exactly what the employer is claiming or contesting.
Q. Can I change my ET1 after it’s submitted?
Yes, but don’t expect to just edit freely. Minor corrections are usually allowed, but if you want to add a new legal claim or rewrite large sections, you’ll need tribunal approval. It’s best to request changes as soon as possible, rather than waiting until later in the process.
Q. What kind of evidence should I include?
Focus on anything that shows what happened and when:
- Employment contracts and payslips
- Emails, letters, and other correspondence
- Disciplinary or grievance notes
- Digital messages (WhatsApp, Slack, Teams) — make sure screenshots show timestamps
Upload these files in PDF, Word, or RTF format. Clear evidence makes it easier for the tribunal to follow your case.
Q. Will the time limits for ET1 claims change in 2026?
Yes. Starting October 2026, most tribunal deadlines are expected to extend from 3 months to 6 months under the Employment Rights Act 2025. Until then, the normal 3-month limit still applies. Even with the extended deadlines, it’s important to notify ACAS within the current time frame — Early Conciliation pauses the clock but doesn’t cancel it.
Conclusion
The ET1 opens a legal case. Everything that follows — hearings, evidence, compensation — flows from what goes into this form.
Three things matter most: submit before the deadline (ACAS Early Conciliation pauses the clock but doesn’t eliminate it), get the ACAS certificate number exactly right, and write a clear factual timeline rather than an emotional account.
With the ACAS conciliation period now running up to 12 weeks, and tribunal time limits set to extend to six months in October 2026, employees in 2026 have more preparation time than ever. Use it.
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