What makes a dismissal “unfair”
A dismissal can be unfair in two ways: the reason wasn’t fair, or the process wasn’t. There are only five potentially fair reasons to dismiss someone:
- Conduct — how you behave at work.
- Capability or performance — your ability to do the job (including ill health).
- Redundancy — your role is genuinely no longer needed (see redundancy pay).
- A legal reason — you can’t legally keep doing the job (a “statutory restriction”).
- Some other substantial reason — a genuine, serious business reason.
Even with a fair reason, the employer must act reasonably and follow a fair procedure — usually warnings, a chance to improve or explain, a proper hearing, and a right of appeal.
The classic unfair sacking
Being dismissed on the spot, with no warning and no process, is often unfair — even if the employer had a reason. How they did it matters as much as why.
Who can claim — and the day-one exceptions
For an ordinary unfair dismissal claim you currently need 2 years’ continuous service. But some dismissals are “automatically unfair” and you can claim them from day one, with no qualifying period — including dismissal for:
- Pregnancy, maternity or taking family leave;
- Whistleblowing (raising a genuine concern about wrongdoing);
- Asserting a statutory right (e.g. asking for the minimum wage or holiday pay);
- Trade union membership or activities;
- Health and safety reasons, or jury service.
Coming change — January 2027
The Employment Rights Act 2025 reduces the qualifying period from 2 years to 6 months and removes the cap on compensation — but this isn’t in force yet; it’s expected from 1 January 2027. The day-one automatically-unfair protections above stay as they are.
Forced to resign? That can be constructive dismissal
If your employer seriously breached your contract and you resigned because of it, that can be constructive dismissal — treated as if they dismissed you. Examples include:
- Not paying you, or a sudden unagreed cut to your pay or hours;
- Bullying or harassment the employer failed to deal with;
- A fundamental change to your role forced on you without agreement.
Get advice before you resign
Constructive dismissal is hard to prove — you have to show a serious breach and that you resigned in response to it. Raising a grievance first usually strengthens your case. Don’t walk out without advice from ACAS or Citizens Advice.
How to claim — and the deadline you can’t miss
- Gather evidence — your contract, payslips, dismissal letter, emails, notes of meetings and any witnesses.
- Start ACAS early conciliation (free). This is required before a tribunal and ACAS will try to resolve it without a hearing — many cases settle here. Notifying ACAS pauses the clock.
- Claim at the employment tribunal if it isn’t resolved.
If you win, a tribunal can order reinstatement, re-engagement or — far more commonly — compensation: a basic award (worked out like statutory redundancy pay) plus a compensatory award for lost earnings. Most cases settle before a hearing.
Do this now
The deadline is strict: usually 3 months less one day from the date your job ended. Start ACAS early conciliation as soon as you can — call ACAS on 0300 123 1100 or use the GOV.UK “make a claim to an employment tribunal” service. Don’t leave it late.
Need the words? Use the letter writer to raise a grievance, and check the rest of your rights at work and any unpaid wages.