What counts as constructive dismissal
You must show that your employer committed a fundamental breach of your contract, that you resigned because of it, and that you did not delay so long that you accepted the breach. Examples include cutting your pay without agreement, demoting you, serious bullying, or a pattern of treatment that destroys trust and confidence.
Unreasonable behaviour alone is not enough. The breach has to be serious. A final incident that is minor on its own can still count if it is the last straw in a series of events.
Before you resign
- Raise a written grievance. It gives your employer the chance to put things right and creates a record. Failing to follow the Acas Code can reduce compensation by up to 25%.
- Collect evidence. Keep emails, messages, notes of meetings and a dated timeline.
- Check your service. You normally need 2 years' service, or 6 months if your employment ends on or after 1 January 2027. See our guide on qualifying service.
- Think about money. Have a plan for income before you leave. Tribunal claims take many months.
- Consider a settlement. A negotiated exit may get you a better result faster.
How to resign
Resign in writing and say clearly that you are resigning because of your employer's breach, listing the main reasons. Do not delay for too long after the last straw, and avoid acts that suggest you accept the changes, such as working under new terms for months without objecting.
Time limits
The tribunal time limit runs from the date your resignation takes effect. For most claims where that date is on or after 1 October 2026, you have 6 months less 1 day, extended by Acas early conciliation. Use the time limit calculator and contact Acas in time.