ET3: What Your Employer Files in Response to Your Tribunal Claim

Once you file your ET1, your employer has 28 days to respond with an ET3. This guide explains what it is, what it must contain, and what the four main legal defences look like.

An ET3 is the form an employer must complete to respond to an employment tribunal claim. After you submit your ET1, the tribunal sends your employer an ET3 and gives them 28 days to respond. In it they state whether they accept or deny your claims and set out their legal defence.

How long does an employer have to file an ET3?

The standard deadline is 28 days from the date the tribunal sends them the ET1. Employers can apply for an extension but it is not guaranteed. Missing the deadline without an extension can bar them from defending the claim.

What happens if the employer does not file an ET3?

The tribunal may bar the employer from defending the claim or proceed without them. Even so, the tribunal still examines your evidence before awarding any remedy.

What are the four main defences employers use in an ET3?

Fair dismissal, denial of the facts, contributory fault, and Polkey reduction.

What are the five potentially fair reasons for dismissal?

Capability, conduct, redundancy, statutory restriction, and some other substantial reason (SOSR).

ET3: What Your Employer Files in Response to Your Tribunal Claim

An ET3 is the official Employment Tribunal response form. When you file your ET1 claim, the tribunal notifies your employer and sends them an ET3, giving them a fixed window to respond. The employer uses it to confirm whether they contest your claim and set out the basis on which they do so.

The ET3 is a public document — both parties receive a copy and it forms part of the case file. It defines the boundaries of your employer's case. They cannot usually introduce arguments at the hearing that were not flagged in the ET3 without the tribunal's permission.

Employers often attach a longer document — sometimes called a Grounds of Resistance — alongside the ET3 form. This is where the detailed narrative of their defence usually appears.

Employers have 28 days from the date the tribunal sends them the ET1 to file their ET3. This is a firm procedural deadline. An employer who misses it without an extension may be barred from defending the claim — the tribunal proceeds without hearing their side.

Extensions are possible but not automatic. The employer must apply before the deadline and demonstrate a genuine reason. Being busy or needing more time to gather documents is generally not sufficient on its own.

If the employer misses the deadline

The tribunal may issue a judgment in your favour or proceed to a hearing the employer cannot attend. Even if they are barred, the tribunal still scrutinises your evidence before deciding remedy — you do not automatically receive everything you claimed.

What Must an ET3 Contain?

The ET3 form requires the employer to state whether they contest the claim and, if so, on what grounds. They must set out:

Any fact not challenged in the ET3 may be treated as admitted. A poorly drafted ET3 that fails to address a point can be significant for your case.

The Four Main Defences Employers Use

Most ET3 responses rely on one or more of four legal arguments. Understanding what each means in law helps you understand the case you are facing.

The employer argues they had a potentially fair reason for dismissing you and followed a fair procedure. This is the most common defence. The legal test is the band of reasonable responses — the tribunal asks whether the decision fell within the range a reasonable employer might have taken, not whether it would have dismissed you itself.

The employer disputes your version of events — that the discrimination occurred, that the treatment you describe happened, or that the facts you rely on are accurate. This turns the case into a credibility dispute. The tribunal decides whose account to prefer based on all the evidence.

Even where a dismissal is found to be unfair, the employer may argue your own conduct contributed to it. If the tribunal agrees, it reduces your compensation proportionally — by 20%, 50%, or more. Contributory fault is assessed separately from whether the dismissal itself was unfair.

Named after Polkey v AE Dayton Services [1988], this applies where the employer argues a fair procedure would have made no difference — they would have dismissed you anyway. If accepted, your compensation is reduced to reflect the probability the outcome would have been the same with a proper process.

The Five Potentially Fair Reasons for Dismissal

To succeed on a fair dismissal defence, an employer must show the dismissal was for one of the five potentially fair reasons in the Employment Rights Act 1996. If they cannot identify and prove a valid reason, the dismissal is automatically unfair — the tribunal does not need to examine procedure.

Performance, ill health, or lack of qualifications. Requires a fair process including warnings and opportunity to improve in most cases.

Misconduct or gross misconduct. The Burchell test applies — genuine belief, reasonable grounds, and a reasonable investigation.

A genuine reduction in need for work of a particular kind. Requires fair selection and, for 20 or more, collective consultation.

Statutory Restriction

Continuing employment would break the law — for example, losing a driving licence required for the role, or losing the right to work.

Some Other Substantial Reason (SOSR)

A catch-all for legitimate business reasons not covered by the other four — a business reorganisation, breakdown of relationships, or expiry of a fixed-term contract.

What Happens After the ET3 Is Filed?

Once both sides have filed their forms, the tribunal issues a case management order — typically setting directions for a preliminary hearing, exchange of witness statements, disclosure of documents, agreement of a hearing bundle, and a final hearing date.

The ET3 shapes how you need to prepare your case. It tells you what facts the employer accepts, what they dispute, and what legal arguments they intend to make. How to respond to the specific arguments in your employer's ET3 is detailed, case-specific work.

Want to understand what your specific ET3 means for your case?

This guide covers what an ET3 is and what the legal defences mean in general terms. The ET3 Analyser in Start My Claim is a paid tool that reads your employer's actual response and explains what their specific arguments mean for your claim. Available on Core and Pro plans.

Build your full case, not just your knowledge

Start My Claim guides you through your ET1, witness statement, schedule of loss, and documents. Free to start, no card required.

ET3 — Frequently Asked Questions

An ET3 is the Employment Tribunal form an employer must complete to respond to your claim. It sets out whether they admit or deny your case and their legal defence. Both sides receive a copy and it forms part of the official case file.

The tribunal may bar the employer from defending the claim or proceed to a hearing without them. Even so, the tribunal still examines your evidence before awarding remedy.

Capability, conduct, redundancy, statutory restriction, and some other substantial reason (SOSR). The employer must identify and prove one of these or the dismissal is automatically unfair.

What is a Polkey reduction?

A reduction to compensation where the tribunal accepts that a fair procedure would have made no difference to the outcome. Named after Polkey v AE Dayton Services [1988]. The tribunal assesses the probability that dismissal would have happened anyway and reduces the award proportionally.

What is contributory fault?

Where the employer argues your own conduct contributed to the dismissal and asks for your compensation to be reduced. The tribunal assesses the degree of fault and reduces the award proportionally. It applies even where the dismissal itself was found unfair.