What do I need to prove to win an unfair dismissal claim?

To succeed, you generally need to show you were dismissed, the reason given was not fair, or the dismissal procedure was unfair. Even if the reason was substantively fair, a procedurally flawed process can still lead to a finding of unfairness or a reduction in the award, known as a Polkey reduction.

What core documents should I collect for my claim?

You should gather the dismissal letter or notice of termination, your employment contract, any written warnings, the invitation to a disciplinary hearing, minutes or notes from that hearing, and any appeal letters you submitted along with their outcomes. These documents help establish the timeline and reasons provided by your employer.

How important is the ACAS Code of Practice in my case?

Tribunals can adjust awards by up to 25% if an employer unreasonably fails to follow the ACAS Code of Practice on Disciplinary and Grievance Procedures. Therefore, keeping a copy of your employer’s disciplinary policy and the ACAS Code is essential to demonstrate the process they were required to follow.

Does evidence that my employer decided the outcome in advance help my case?

Yes, evidence that the employer had pre-determined the outcome before the disciplinary process began can be powerful in demonstrating procedural unfairness. This includes any correspondence or witness statements from colleagues that suggest the decision was made before the hearing took place.

What performance records are relevant to an unfair dismissal claim?

You should collect performance reviews, appraisals, any performance improvement plans, and records of previous disciplinary issues. Additionally, gather evidence showing you met targets or performance standards. These records help contextualize the dismissal and support your position regarding your conduct and performance.

← All Checklists

evidence

Employment Law

Updated 2026-04-09

Evidence Checklist for an Unfair Dismissal Claim

Key documents and records to support an unfair dismissal claim under the Employment Rights Act 1996.

Overview

To succeed in an unfair dismissal claim, you generally need to show: (1) you were dismissed; (2) the reason given was not a fair reason, or; (3) the dismissal procedure was unfair (Polkey v AE Dayton Services [1987]). Gather every document relating to the dismissal process. Even if the reason was fair in substance, a procedurally flawed process can still lead to a finding of unfairness or a Polkey reduction.

0 of 14 items checked

Core Dismissal Documents

Dismissal letter or notice of termination(Essential)

Establishes the date of dismissal and the reason given — the clock for your claim starts here

Employment contract and written statement of particulars(Essential)

Any earlier written warnings (first written, final written)(Essential)

Invitation to disciplinary hearing letter(Essential)

Minutes or notes of the disciplinary hearing(Essential)

Appeal letter you submitted (if any) and outcome

Performance and Conduct Records

Performance reviews and appraisals

Any performance improvement plan (PIP)

Records of any previous disciplinary issues

Evidence that you met targets or performance standards

Procedural Evidence

Employer's disciplinary policy and procedure(Essential)

Establishes the process your employer said they would follow (ACAS Code of Practice on Disciplinary and Grievance Procedures)

ACAS Code of Practice on Disciplinary and Grievance Procedures

Tribunals adjust awards by up to 25% for unreasonable failure to follow the Code

Witness statements from colleagues who can speak to the facts

Any correspondence showing the employer had pre-determined the outcome

Evidence of pre-determination can be powerful in showing procedural unfairness

Related Guides

Related Rights

Official Resources

ACAS Code of Practice on Disciplinary and Grievance Procedures →Employment Tribunals →

Frequently asked questions

What do I need to prove to win an unfair dismissal claim?: To succeed, you generally need to show you were dismissed, the reason given was not fair, or the dismissal procedure was unfair. Even if the reason was substantively fair, a procedurally flawed process can still lead to a finding of unfairness or a reduction in the award, known as a Polkey reduction.
What core documents should I collect for my claim?: You should gather the dismissal letter or notice of termination, your employment contract, any written warnings, the invitation to a disciplinary hearing, minutes or notes from that hearing, and any appeal letters you submitted along with their outcomes. These documents help establish the timeline and reasons provided by your employer.
How important is the ACAS Code of Practice in my case?: Tribunals can adjust awards by up to 25% if an employer unreasonably fails to follow the ACAS Code of Practice on Disciplinary and Grievance Procedures. Therefore, keeping a copy of your employer’s disciplinary policy and the ACAS Code is essential to demonstrate the process they were required to follow.
Does evidence that my employer decided the outcome in advance help my case?: Yes, evidence that the employer had pre-determined the outcome before the disciplinary process began can be powerful in demonstrating procedural unfairness. This includes any correspondence or witness statements from colleagues that suggest the decision was made before the hearing took place.
What performance records are relevant to an unfair dismissal claim?: You should collect performance reviews, appraisals, any performance improvement plans, and records of previous disciplinary issues. Additionally, gather evidence showing you met targets or performance standards. These records help contextualize the dismissal and support your position regarding your conduct and performance.