Unfair dismissal: what UK employers need to know
Most dismissals are lost not on the reason but on the process. Understanding what 'fair' means is the best protection you have.
The qualifying period
Ordinarily an employee needs two years' continuous service to claim ordinary unfair dismissal - but 'automatically unfair' reasons (such as pregnancy, whistleblowing, or asserting a statutory right) have no qualifying period.
The five fair reasons
- Conduct, capability or performance, redundancy, illegality (e.g. losing the right to work), or 'some other substantial reason'.
The fairness test
Even with a fair reason, the dismissal must be handled fairly - a reasonable investigation, following the ACAS Code, and dismissal within the 'band of reasonable responses'. Process failures are the most common reason employers lose.
Last reviewed September 2026. General information, not legal advice - check ACAS and GOV.UK for your situation.
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