Unfair dismissal is when an employer dismisses an employee without a fair reason or without following a fair procedure. In England, Scotland and Wales you normally need 2 years' service to claim, and that's due to fall to 6 months in January 2027 under the Employment Rights Act 2025. Some reasons are automatically unfair from day one.
Whether you're an employer letting someone go or an employee who thinks you've been treated badly, the rules turn on three questions: why it happened, how it was done, and how long the person had worked there. Here's what GOV.UK and Acas say.
The five fair reasons for dismissal
GOV.UK lists situations where an employer can dismiss fairly. In each case the employer still has to act reasonably, be consistent and investigate the situation fully.
| Reason | What it covers | What the employer should do first |
|---|---|---|
| Capability | Not able to do the job, or a long-term illness that makes the job impossible | Follow disciplinary procedures, give a chance to improve, support and give reasonable time to recover |
| Conduct | Misconduct, including gross misconduct such as violence | Investigate, even in gross misconduct cases |
| Redundancy | The job is no longer needed | Use a fair selection process |
| Breaking the law | Continuing to employ someone would be illegal, such as a driver losing their licence | Check there's no lawful alternative |
| Some other substantial reason | For example, unreasonably refusing a reorganisation that changes terms | Act reasonably and consistently |
Dismissal because of a disability may be unlawful discrimination, and the employer has a legal duty to support disability in the workplace.
The qualifying period, and what's changing
Under the current rules, you must be an employee and have worked for your employer for a minimum period, normally 2 years, before you can claim unfair dismissal at a tribunal. In Northern Ireland it's normally 1 year.
This is the change every employer should plan for. Acas says that protection from unfair dismissal will become a right after 6 months in a job, as part of the Employment Rights Act 2025, and that the change will happen in January 2027 and isn't yet law. Acas also says that in January 2027 'fire and rehire', dismissing someone and rehiring them on worse terms, will become an automatically unfair dismissal in most cases.
In practice, that means your probation reviews need to happen inside six months, with written records, rather than relying on the two-year window.
Automatically unfair reasons
Some reasons are automatically unfair, and Acas says an employee doesn't need 2 years' service to claim. They include dismissing someone for:
- Wanting to take family leave, such as maternity, paternity or adoption leave
- Asking for a legal right, such as being paid the National Minimum Wage
- Taking, or proposing to take, action over a health and safety issue
- Taking part in official industrial action, or exposing wrongdoing at work (whistleblowing)
- Refusing to give up working time rights, such as rest breaks
- Political opinions or affiliation, for dismissals since 25 June 2013
A discrimination claim linked to a protected characteristic, such as race or sex, doesn't need 2 years' service either.
What a fair procedure looks like
Acas says a fair procedure for misconduct or capability should follow the Acas Code of Practice on disciplinary and grievance procedures, and that a fair procedure is still expected for other reasons. The Code itself says employers should carry out any necessary investigations to establish the facts, raise and deal with issues promptly, allow employees to be accompanied at any formal disciplinary meeting, and allow an appeal against any formal decision. In misconduct cases, where practicable, different people should carry out the investigation and the disciplinary hearing. Employers who skip steps can turn a fair reason into an unfair dismissal. For someone with less than 2 years' service, Acas calls it a short service dismissal and says they'll need to check which other rights apply.
Constructive dismissal
Constructive dismissal is when you're forced to resign because of your employer's conduct. GOV.UK's examples include not paying you, demoting you suddenly for no reason, or forcing unreasonable changes, such as night shifts when your contract is for days. It can be one serious incident or a series of incidents. GOV.UK's advice is to leave immediately if you have a case, because staying could be taken as accepting the treatment.
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Your rights when you're dismissed
- Notice: at least your contractual notice or the statutory minimum, whichever is longer, except for gross misconduct.
- Written reasons: employees with 2 years' service can ask for a written statement of reasons, which the employer must supply within 14 days.
- Pregnancy and maternity: if you're dismissed during Statutory Maternity Leave, you get a written statement regardless of how long you've worked there.
- An appeal: Acas says being able to appeal is part of its Code of Practice, and the employer should explain how.
Time limits for a tribunal claim
Time limits have just changed, so check carefully. GOV.UK says you usually have to claim within 6 months of being dismissed, and if you were dismissed before 1 October 2026 you may need to claim within 3 months. You'd normally try to resolve it first through your employer's appeal, mediation or conciliation.
Workers, as opposed to employees, can't claim unfair dismissal, which matters for casual staff on zero hours contracts. For employers, HR software keeps the records a fair procedure depends on, and UK payroll software gets notice pay and final pay right.
My verdict
Unfair dismissal law is about reason and process, not just length of service. With the qualifying period falling to six months in January 2027 and the claim window now six months, the safe approach is the same for every hire: clear expectations, written reviews, a fair procedure and a right to appeal. Employers who do that rarely end up at a tribunal.
Frequently asked questions
How long do you need to work to claim unfair dismissal?
Normally 2 years as an employee in England, Scotland and Wales, and 1 year in Northern Ireland. Acas says this will fall to 6 months in January 2027.
What are automatically unfair reasons for dismissal?
They include dismissal for wanting family leave, asking for a legal right such as the minimum wage, health and safety action, whistleblowing and official industrial action. No qualifying period applies.
What is the time limit for an unfair dismissal claim?
GOV.UK says you usually have 6 months from dismissal. If you were dismissed before 1 October 2026, you may need to claim within 3 months.
Can a worker claim unfair dismissal?
No. Only employees can claim unfair dismissal. Workers may have other claims, such as for detriment.
What is constructive dismissal?
When you're forced to leave because of your employer's serious conduct, such as not paying you or forcing unreasonable changes to how you work.
Will fire and rehire be banned?
Acas says that in January 2027 fire and rehire will become an automatically unfair dismissal in most cases, under the Employment Rights Act 2025.
