Form ET3: how a UK employer responds to a tribunal claim

An employment tribunal claim starts when an employee files Form ET1. Your turn to respond comes next, on a strict 28-day deadline. Form ET3 is the official document the court provides for you to set out your defence. This guide walks you through every section, the timing rules, and what happens after you file.

The short version

When an employee sues you in the employment tribunal, you must file Form ET3 within 28 days of receiving the ET1 claim. ET3 has five sections: your details, the claimant's details, your response to each allegation (yes, no, or partly), your detailed defence narrative, and your representative's details if you have one. File it late and the tribunal can refuse to hear your case. File it on time and you move into case management, where both sides exchange evidence and prepare for a hearing.

At a glance

What Form ET3 is

Form ET3 is the tribunal's official response template. It is not a free-text letter; it has prescribed sections that help you structure your defence in a way the tribunal expects. The form forces clarity. You cannot argue your case in paragraph form alone. You must answer yes, no, or partly to each allegation the claimant makes, then explain why in a separate grounds section.

The tribunal publishes ET3 on its website. You can download it as a PDF, fill it in by hand or on your computer, and return it. Some employers use a solicitor; others do it themselves. Either way, the same form applies.

The tone of ET3 matters. The tribunal will read it to understand your position. Rambling, angry, or defensive language harms your case. Keep it factual, professional, and specific.

When the clock starts: 28 days from receipt

The 28-day clock does not start when you think. It starts when the tribunal sends the ET1 to you, the respondent. The letter containing the ET1 will state the date it was posted or sent. You count 28 days from that date.

If the ET1 was sent by first-class post, the tribunal assumes you received it on the second working day after it was posted. If sent electronically, receipt is immediate. If you received it by hand, the date of hand-delivery is the start date.

Missing the 28-day deadline is serious. The tribunal can strike out your ET3, meaning your response is not heard, and the case proceeds without your input. In rare cases, the tribunal will allow a late response if you can show good reason (illness, representation failure, postal error). But do not rely on this.

Section 1: respondent details

Section 1 asks for your name, address, telephone number, email address, and legal status (sole trader, partnership, limited company, etc.). This is straightforward. Give your registered address, not a care-of address. If you are a limited company, give the registered office address.

The tribunal uses this section to contact you and to identify you in the case title. For example, the case might be titled "Smith v Acme Ltd (a limited company)". Get the company name and address right. Mistakes here cause delays.

If you are represented by a solicitor or barrister, you must still complete Section 1 with your own details. The representative's details go in Section 5.

Section 2: claimant details

Section 2 asks you to verify the claimant's name, address, and job title as stated in the ET1. This is a check. Look at the ET1 and copy the claimant's details exactly as they appear. If the claimant's address has changed and you have a more recent one, you can note this, but use the address from the ET1 as the baseline.

If the claimant is represented by a solicitor or trade union, confirm their representative's details too. This ensures the tribunal sends copies to the right person.

Section 3: defending the claim: yes, no, or partly

Section 3 is the first major section. The ET1 contains allegations, complaints, or claims. The claimant might say you dismissed them unfairly, or discriminated against them, or failed to pay them. For each allegation, you must state whether you admit it, deny it, or partly admit it.

Admit: You accept the allegation as true. For example, if the claimant says you paid them less than the minimum wage, and you did, write "Admit".

Deny: You reject the allegation. You are saying it is not true or not as the claimant describes it. Write "Deny".

Partly admit: The allegation is partly true but you contest part of it. Write "Partly admit" and briefly note which part you accept. For example, "Partly admit: we did dismiss the claimant, but not without fair process."

Do not leave any allegation unanswered. Every claim requires a response.

If you deny an allegation, you are signalling that the claimant must prove it at the hearing. You do not have to prove your denial; you must merely dispute the claimant's version.

If you admit an allegation, you have limited grounds to contest it later. Only admit facts you are genuinely willing to accept.

Section 4: grounds of resistance

Section 4 is the narrative heart of ET3. Here you set out your detailed defence. You have space (usually 10 pages) to explain why the claimant's claims fail.

This is where you tell your story. Why was the claimant dismissed? What policies did you follow? What evidence supports your version? If the claimant claims discrimination, how can you explain the treatment they describe?

Write in clear, chronological order. Cite dates, names, and documents where possible. For example:

"The claimant was dismissed on 15 March 2025. The reason for dismissal was poor performance. We had issued a first written warning on 1 December 2024 following the claimant's failure to meet sales targets for three consecutive months. The targets were £50,000 per month; the claimant achieved £32,000, £35,000, and £28,000 respectively. We offered support via mentoring by the top performer, John Smith. The claimant declined mentoring on 12 December. On 10 March, we held a performance review and gave a second written warning. On 15 March, following a further month of underperformance (£25,000), we held a dismissal meeting..."

This is not the place to be emotional or defensive. Stick to facts. Let the evidence speak.

If there are many allegations, number your responses. For example:

"1. Allegation of unfair dismissal - we deny this. 2. Allegation of discrimination on grounds of race - we deny this. 3. Allegation of failure to pay commission - we partly admit we were late, but dispute the amount."

The tribunal will read this section carefully. Contradictions between Section 3 and Section 4 will be noted. Make sure they align.

Section 5: representative details

If you are represented by a solicitor, barrister, or employment law specialist, give their full name, firm name, address, telephone, and email in Section 5. The tribunal will send copies of all future documents to your representative, not to you directly.

If you are acting for yourself (a litigant in person), leave Section 5 blank or write "None". The tribunal will contact you at the address in Section 1.

Some employers use an accountant or HR consultant who is not legally qualified. If that person is not a lawyer, do not list them in Section 5. Instead, note in a covering letter that they are assisting but are not your representative. The tribunal can only recognise certain types of representative (solicitors, barristers, certain trade union officials, and certain accredited representatives).

How to plead unfair dismissal defence

Unfair dismissal is the most common claim. The claimant must prove they were dismissed. You must then show one of five potentially fair reasons for the dismissal:

1. Conduct: The employee was guilty of gross misconduct or gross breach of contract. Example: theft, violence, or serious insubordination.

2. Capability: The employee was incapable of doing the job due to illness, lack of skill, or qualification. Example: inability to meet targets despite support, lack of required certification, or long-term absence.

3. Redundancy: The role or business ceased, or reduced demand meant fewer staff were needed. Example: the department closed, or the company restructured and consolidated roles.

4. Statutory restriction: It would be unlawful to continue employing the person. Example: a taxi driver who loses their licence.

5. Some other substantial reason: This is a catch-all for reasons that do not fit above. Example: breakdown of trust and confidence, or reorganisation.

In your ET3, state which reason applies. Then explain the facts that support it. For unfair dismissal, the tribunal also examines whether you followed a fair process. Did you investigate? Did you give the employee a chance to respond? Did you consider appeals? Did you consider alternatives (redeployment, support, demotion)?

Example grounds of resistance for unfair dismissal:

"The claimant was dismissed for gross misconduct. On 1 April 2025, we received a complaint from a customer that the claimant had been rude and abusive during a service call. We conducted an investigation on 5 April. The claimant admitted raising their voice but said the customer was rude first. We reviewed the call recording. The claimant used profanity directed at the customer. We consider this a breach of our Customer Care Policy (issued to all staff on 1 June 2024 and signed for by the claimant on 2 June). We held a disciplinary hearing on 10 April. The claimant was represented by a colleague. We gave the claimant a chance to respond. We upheld the complaint and dismissed for gross misconduct. This is a fair reason and a fair process was followed."

How to plead discrimination defence

Discrimination claims are common too. The claimant alleges they were treated worse because of a protected characteristic (race, sex, age, disability, religion, sexual orientation, etc.).

Your defence has three possible routes:

1. Denial: It did not happen as the claimant describes. You did not make the comment, do not recall the event, or have a different account. Provide facts that contradict the claimant's version.

2. Non-reliance: Even if it happened, it was not because of the protected characteristic. You would have done the same to anyone else. Provide evidence of how you treated others in similar situations.

3. Justification: For indirect discrimination only. The claimant was treated as required by the role, or the difference in treatment is a genuine occupational requirement. Example: a care home can require women to care for women in certain roles.

Example grounds of resistance for discrimination:

"The claimant alleges sex discrimination in pay. We deny this. The claimant was paid £35,000. We have three other employees in the same role. Their pay is: Employee A (female) £36,000, Employee B (male) £34,500, Employee C (female) £37,000. The claimant's pay was set based on their experience and previous salary. The claimant had less experience than Employees A and C. The claimant's starting salary was negotiated with the claimant at £33,000 and increased to £35,000 after one year. No sex discrimination has occurred."

Late filing and extension applications

If you miss the 28-day deadline, you have not lost all hope, but your options are limited. You can apply to the tribunal for an extension. The tribunal will grant it only if you have a good reason.

Good reasons include:

• Illness or incapacity during the deadline period
• Postal delay or failure (if you can evidence this)
• Your representative's negligence (though this is a weak argument unless the firm was dishonest or entirely uncontactable)
• Misunderstanding of the rules (weaker than above)

Bad reasons include:

• You were too busy
• You did not think the deadline was real
• You assumed the tribunal would remind you

If you seek an extension, you must apply in writing before or shortly after the deadline. State your reason clearly and provide evidence. Your full ET3 should accompany the application.

The tribunal will decide whether to grant the extension. Even if it does, the tribunal may make a costs order against you if the delay has caused prejudice (for example, the claimant had to take extra steps to prepare).

To avoid this drama, file ET3 on time. Do your calculations now. Look at the date the ET1 was sent. Count 28 days forward on a calendar. That is your deadline. Set a reminder a week before.

What happens after filing: case management and beyond

Once you file ET3, the case enters case management. The tribunal will:

1. Send a case management conference letter: Within 2 weeks, you will receive notice of a case management conference (CMC). This is a telephone or video hearing where the judge and both parties discuss the scope of the case, what evidence is needed, and realistic timescales. You do not present your case; you discuss its management.

2. Request disclosure: Both sides must disclose documents relevant to the claims. This is called disclosure. You must provide emails, performance reviews, disciplinary records, HR policies, minutes of meetings, anything relevant. The claimant must do the same. Failure to disclose can lead to sanctions.

3. Request witness statements: Each side prepares written statements from anyone with relevant knowledge. You might prepare statements from your manager, HR person, colleagues, or the claimant's supervisor. These statements are served on the claimant in advance.

4. Build the bundle: A joint document bundle is prepared containing all disclosed documents, cross-referenced and paginated. This is what the tribunal will read at the hearing.

5. Prepare for hearing: The tribunal will set a hearing date, usually 4 to 6 months after ET1 is filed (though backlogs vary). You prepare your oral evidence and cross-examination points.

Do not relax after filing ET3. The case is far from over. Many claims settle in the months between ET3 filing and hearing. Others proceed to trial.

Day to day: a timeline

Here is what you can expect:

This timeline can stretch if the case is complex or the tribunal is busy. But it gives you a sense of the pace.

Common misconceptions

Misconception 1: ET3 is optional. False. If you do not file, the tribunal will assume your response is "no response" and may proceed without hearing from you.

Misconception 2: You must admit the allegation if you cannot disprove it. False. Denying does not mean you have to prove the claimant wrong. They must prove their case. You deny and put them to proof.

Misconception 3: Writing a long, emotional ET3 strengthens your case. False. Longer does not mean better. Stick to facts. Remove feelings. A crisp, well-organised 3-page defence beats a rambling 20-page rant.

Misconception 4: You can ignore the tribunal's CMC order or disclosure request. False. Ignoring tribunal orders risks a judgment against you and can lead to costs orders.

Misconception 5: Once you file ET3, you are done. False. ET3 is the start of a long case. You must actively engage in disclosure, prepare witnesses, and attend the hearing.

Related concepts

• Form ET1: how to understand an employment tribunal claim
• Unfair dismissal: what makes a dismissal unfair
• Discrimination in the workplace: the five protected grounds
• Employment tribunal hearing: what to expect
• Witness statements: how to prepare and structure them
• Disclosure of documents in tribunal claims
• Settlement and ACAS conciliation

Sources

• Gov.uk Employment Tribunals - Official guidance on tribunal claims and procedures.
• ACAS: Responding to an employment tribunal claim - Employer guidance on responding to ET1.
• UK Judiciary: Employment Tribunals Rules of Procedure - The procedural rules governing tribunal claims.

Written by Peter Kolomiets, founder of CaseCalm. UK employment law content reviewed 2026-05-28.

Disclaimer: This page provides information about UK Form ET3. It is not legal advice. Every tribunal claim is unique. If you are facing a tribunal claim, consult a qualified employment law solicitor.