The 5 Fair Reasons for Dismissal: What Your Employer Must Prove
Last updated: December 2025 Applies to: England, Wales and Scotland. Not tailored to Northern Ireland.
Important: This guide provides information about UK employment law. It is not legal advice. Every situation is different. If you've been dismissed and want to understand your options, consider speaking to a solicitor for advice specific to your circumstances.
The Basics
Under the Employment Rights Act 1996, an employer who dismisses someone with 2+ years' service must show they had a potentially fair reason from one of five categories.
Having a fair reason isn't enough on its own. The employer must also show they acted reasonably and followed a fair process.
If they can't, the dismissal may be unfair.
| Reason | What It Means |
|---|---|
| Capability | You can't do the job (performance or health) |
| Conduct | You did something wrong |
| Redundancy | The job no longer exists |
| Statutory illegality | Continuing to employ you would break the law |
| Some other substantial reason (SOSR) | Catch-all for other genuine business reasons |
1. Capability
Capability means the employee can't do the job to the required standard. This covers two situations: performance and health.
Performance
If an employer says you weren't performing, they should have:
- Told you specifically what was wrong
- Given you a chance to improve (usually a performance improvement plan)
- Provided training or support where needed
- Set clear, achievable targets with a reasonable timeframe
- Warned you that dismissal was a possibility if things didn't improve
Dismissing someone for poor performance without warnings, targets, or support may be procedurally unfair.
Health
Long-term sickness can fall under capability. But employers can't simply dismiss someone for being ill. They should:
- Get up-to-date medical evidence (usually an occupational health report)
- Consult with you about your condition and prognosis
- Consider reasonable adjustments
- Consider alternative roles if available
- Only dismiss as a last resort after exploring options
If you have a disability under the Equality Act 2010, dismissing you without considering adjustments could be discrimination as well as unfair dismissal.
Challenging a capability dismissal: Did they give you a real chance to improve? Did they get proper medical evidence? Did they consider adjustments? If not, the process may have been unfair.
2. Conduct
Conduct means behaviour that breaches workplace rules or standards. It ranges from minor issues to gross misconduct.
Ordinary misconduct
Repeated lateness, minor rule breaches, poor attitude. Usually requires warnings before dismissal.
Gross misconduct
Serious one-off acts like theft, violence, fraud, serious insubordination. Can justify immediate dismissal without notice (summary dismissal).
But even with gross misconduct, the employer should still:
- Investigate properly before deciding
- Tell you the allegations in writing
- Give you a chance to respond at a disciplinary hearing
- Allow you to be accompanied (colleague or trade union rep)
- Make a balanced decision based on evidence
- Offer a right of appeal
A knee-jerk dismissal without investigation, even for something serious, can still be unfair.
Challenging a conduct dismissal: Was there a proper investigation? Did you get a chance to give your side? Was dismissal proportionate, or would a warning have been more appropriate? Did they treat others in similar situations the same way?
3. Redundancy
Redundancy means the job itself is disappearing. The work has reduced, the business is closing, or the role is no longer needed.
Redundancy is a fair reason, but the process can still be unfair. The employer should:
- Show a genuine redundancy situation exists (not just wanting to remove you)
- Consult with you before making a final decision
- Consider you for alternative roles
- Use fair and objective selection criteria if choosing between employees
- Apply those criteria consistently
If you were "selected for redundancy" but the real reason was something else (your pregnancy, your grievance, your whistleblowing), that may not be genuine redundancy. It could be automatically unfair dismissal.
Challenging a redundancy dismissal: Was the redundancy genuine? Were the selection criteria fair and applied properly? Were you considered for other roles? Was someone else hired to do your job afterwards?
4. Statutory Illegality
This applies when continuing to employ someone would break the law.
Common examples:
- A driver loses their driving licence
- Someone's visa or right to work expires
- A professional loses a required qualification or registration
The employer should still check if there's any alternative before dismissing. If a driver loses their licence, could they do office-based work instead? The employer should explore options before concluding dismissal is the only route.
Challenging a statutory illegality dismissal: Did they explore alternatives? Was the legal restriction genuine and verified? Could you have been redeployed?
5. Some Other Substantial Reason (SOSR)
SOSR is a catch-all for situations that don't fit the other four but still amount to a genuine business reason.
Examples:
- Breakdown in working relationships that can't be resolved
- Refusal to accept reasonable changes to terms and conditions
- End of a temporary contract covering maternity leave
- Reputational risk from an employee's conduct outside work
- Pressure from a major client to remove someone
SOSR is often misused. Employers sometimes claim SOSR when the real reason is something else. Tribunals look at whether the reason was genuinely substantial and whether dismissal was a reasonable response.
Challenging an SOSR dismissal: Was the reason genuinely substantial, or a pretext? Did they explore alternatives? Was the process fair?
Fair Reason Isn't Enough
Even with a valid reason, the dismissal can be unfair if the employer:
- Didn't investigate properly
- Didn't follow their own procedures
- Didn't give you a chance to respond
- Didn't consider alternatives to dismissal
- Treated you differently from others in similar situations
- Made the decision before the process was complete
The ACAS Code of Practice on disciplinary and grievance procedures sets the baseline. Failure to follow it can lead to a 25% uplift on compensation if you win at tribunal.
What If the Reason Given Isn't the Real Reason?
Sometimes employers give one reason, but the real reason is something else.
If the true reason was pregnancy, whistleblowing, trade union activity, or another protected ground, the dismissal could be automatically unfair regardless of your length of service.
For example:
- Employer says "redundancy" but you're the only one affected, and they hire someone else
- Employer says "performance" but never raised concerns until you submitted a grievance
- Employer says "conduct" but the real issue is your disability-related absences
If you suspect the stated reason is a cover, look at the timing, the lack of evidence, and how others were treated.
ERA 2025: What's Changing
The Employment Rights Act 2025 (Royal Assent 18 December 2025) brings changes:
| Change | When |
|---|---|
| Qualifying period drops from 2 years to 6 months | 1 January 2027 |
| Compensation cap abolished | 2027 (date TBC) |
| Tribunal time limits extended to 6 months | October 2026 |
From January 2027, more employees will be protected. If you have 6+ months' service, you'll be able to challenge whether your employer had a fair reason.
Time Limits
If you think your dismissal was unfair:
| Step | Deadline |
|---|---|
| Contact ACAS for Early Conciliation | Within 3 months minus 1 day of dismissal |
| Submit ET1 to tribunal | Within 1 month of ACAS certificate |
Don't wait. These deadlines are strict.
What To Do If You've Been Dismissed
Get the reason in writing. If you have 2+ years' service, you have the right to request written reasons. Your employer must respond within 14 days.
Check the stated reason against what actually happened. Does it add up?
Review the process. Were you told the allegations? Given a chance to respond? Offered an appeal?
Note your dismissal date. Calculate your 3-month deadline.
Contact ACAS on 0300 123 1100 for guidance.
Seek legal advice when unsure, if compensation could be significant or the case is complex.
How Yerty Can Help
For more on unfair dismissal claims, including eligibility guidance, deadline information, evidence checklists, and next steps, see our Unfair Dismissal Claims package.
Frequently Asked Questions
What are the 5 fair reasons for dismissal?
Capability, conduct, redundancy, statutory illegality, and some other substantial reason (SOSR). These are set out in section 98 of the Employment Rights Act 1996.
Can my employer dismiss me for any of these reasons?
Only if they also follow a fair process. Having a potentially fair reason is necessary but not sufficient. The employer must act reasonably and follow proper procedures.
What if I have less than 2 years' service?
You can't claim ordinary unfair dismissal, but you may still have claims for automatically unfair dismissal, discrimination, or wrongful dismissal. See our guide: Unfair Dismissal Under 2 Years: Can You Still Claim?
What if the reason given isn't the real reason?
If the true reason was discriminatory or automatically unfair (pregnancy, whistleblowing, etc.), you may have a claim regardless of what the employer says.
Sources
Legislation:
- Employment Rights Act 1996, s.98: www.legislation.gov.uk/ukpga/1996/18/section/98
- Employment Rights Act 2025: www.legislation.gov.uk
- Equality Act 2010: www.legislation.gov.uk/ukpga/2010/15/contents
Official guidance:
- ACAS Code of Practice on disciplinary and grievance procedures: www.acas.org.uk/acas-code-of-practice-on-disciplinary-and-grievance-procedures
- Gov.uk, Dismissal: www.gov.uk/dismissal