Constructive Dismissal vs Unfair Dismissal: UK Rules Compared 2026/27

The key structural difference

The simplest way to distinguish these two claims is to ask: who ended the employment?

• In unfair dismissal, the employer terminates the contract — through dismissal, redundancy, or non-renewal of a fixed-term contract — and the employee challenges whether the reason and process were fair.
• In constructive dismissal, the employee resigns, but argues that the resignation was forced by the employer's conduct — a fundamental breach of the employment contract so serious that the employee had no real choice but to leave.

Constructive dismissal claims are usually then pursued as a form of unfair dismissal (sometimes called "constructive unfair dismissal") — the employee has to prove both that a dismissal effectively occurred (via the employer's breach) and that it was unfair.

What counts as a fundamental breach for constructive dismissal

Not every unpleasant workplace situation qualifies. The breach has to go to the heart of the employment relationship — commonly recognised examples include:

• Unilaterally and significantly cutting an employee's pay or demoting them without agreement or contractual right.
• Persistent failure to pay wages on time or in full.
• A serious breach of the implied term of trust and confidence — such as bullying, harassment, or humiliating treatment condoned by management.
• Making unreasonable, unilateral changes to core terms like hours, location, or duties without consultation or contractual right.

Crucially, the employee must resign in response to the breach, and generally without significant delay — waiting too long after the breach before resigning can be seen as accepting the change (known as "affirming the contract"), which can undermine the claim.

Qualifying service and exceptions

Both claim types normally require the employee to have two years' continuous service with the employer before the effective date of termination. However, this qualifying period does not apply in certain categories, including where the real reason relates to:

• Whistleblowing (making a protected disclosure)
• Certain types of discrimination (age, sex, race, disability, religion, sexual orientation, pregnancy/maternity, gender reassignment)
• Asserting a statutory right (such as requesting flexible working or minimum wage entitlement)
• Health and safety reasons in specified circumstances

An employee with less than two years' service but who can show the real reason falls into one of these categories may still be able to bring a claim despite the short service.

Time limits

Both types of claim must generally be lodged with an employment tribunal within three months less one day of the "effective date of termination" — for constructive dismissal, this is usually the date the resignation takes effect, not the date of the underlying breach. ACAS early conciliation, which is compulsory before most tribunal claims, can extend this window slightly while conciliation is attempted, but it is easy to miss the deadline if someone delays acting while trying to resolve matters informally.

Tax treatment of compensation

If a claim succeeds (or is settled), any resulting payment is generally taxed the same way regardless of whether it arose from unfair or constructive dismissal:

• Any element representing notice pay or PILON is taxed in full as earnings (Income Tax and Class 1 NI).
• Genuine compensation for loss of office can usually benefit from the £30,000 tax-free termination payment exemption, with any excess above £30,000 taxed as income (though not subject to employee NI).
• Legal costs paid directly by the employer to the employee's solicitor under a settlement agreement are often treated separately and can be tax-free if paid directly to the solicitor for advice on the settlement.

Practical takeaway

If you are considering resigning because of your employer's conduct, take advice before resigning wherever possible — once you resign, the burden is on you to prove the breach was serious enough to justify treating it as a dismissal, whereas in a straightforward unfair dismissal the employer has already made the decision to end the employment and must justify it.