Unfair Dismissal UK: Your Rights and the 2027 Change

In Great Britain, most employees need two years' continuous service before they can bring an unfair dismissal claim, but that qualifying period is falling to six months from 1 January 2027 under the Employment Rights Act 2025 (Northern Ireland has a one-year rule). Some dismissals, however, are unfair from an employee's very first day.

What Counts as Unfair Dismissal

Under Part X of the Employment Rights Act 1996, a dismissal is unfair unless the employer can show it was for one of five potentially fair reasons and that the decision, and the process followed, fell within the "band of reasonable responses" a reasonable employer might take. A tribunal does not simply ask whether it would have dismissed the employee; it asks whether this employer's decision was one a reasonable employer could have reached, given the reason and the procedure used. A fair reason on its own is not enough. Where an employee resigns in response to a fundamental breach of contract, that can instead amount to constructive dismissal, and where the stated reason is conduct, the fairness of the process often turns on whether the employer properly treated the matter as gross misconduct justifying dismissal without notice.

The Qualifying Period: 2 Years, Falling to 6 Months from 1 January 2027

To bring an ordinary unfair dismissal claim, an employee currently needs two years' continuous service with their employer. The Employment Rights Act 2025 shortens that qualifying period to six months, with the change taking effect from 1 January 2027. This is a reduction in the length of service required, not a move to a day-one right; employees who have not yet reached the new six-month threshold when it comes into force will generally still be unable to bring an ordinary unfair dismissal claim. What decides which rule applies is the effective date of termination (usually the last day of employment, after any notice), not the date notice is given. The six-month rule applies wherever the effective date of termination falls on or after 1 January 2027, even if notice of dismissal was given before then; where it falls before 1 January 2027, the two-year rule still applies. The reform sits alongside a wider set of Employment Rights Act 2025 changes phased in across 2026 and 2027, including statutory sick pay, redundancy pay uprating, and a new Fair Work Agency enforcement body.

Automatically Unfair Reasons That Need No Qualifying Service

A separate category of dismissal is automatically unfair regardless of length of service, because no qualifying period applies at all. These day-one protections exist because certain reasons for dismissal are treated as unacceptable whatever the employee's tenure.

These grounds are separate from the qualifying-period reform above and do not depend on it. Apart from pregnancy and maternity, a dismissal because of a protected characteristic, such as sex, race or disability, is not in itself one of these automatically unfair reasons under the Employment Rights Act 1996, but it can be challenged as unlawful discrimination under the Equality Act 2010, a separate claim that does not depend on the unfair dismissal qualifying period. An employee dismissed for whistleblowing on their first day at work can already bring a claim, before or after the 2027 change alike.

The Five Potentially Fair Reasons for Dismissal

Where an employee does have the necessary qualifying service, an employer defending an unfair dismissal claim must show the real reason for dismissal falls within one of five categories set out in the Employment Rights Act 1996.

A fair reason alone does not make a dismissal fair. The employer must also follow a reasonable procedure, which typically means an investigation, a hearing, and a right of appeal appropriate to the circumstances.

Remedies: Reinstatement, Re-engagement and Compensation

A tribunal that finds a dismissal unfair can order reinstatement (the employee returns to their old job) or re-engagement (a comparable job with the same employer), though both are rare in practice; compensation is the usual outcome. Compensation has two elements. The basic award is calculated using the same formula as statutory redundancy pay: age-banded weeks of pay for each full year of service, capped at 20 years and at a maximum week's pay of £751. The compensatory award covers the employee's actual financial loss, such as lost earnings and benefits, and currently sits under a statutory cap. That cap is being removed under the Employment Rights Act 2025, alongside the shortened qualifying period, where the effective date of termination is on or after 1 January 2027. Tribunals can also reduce either award, for example where the employee contributed to their own dismissal.

Our free UK Employment Tribunal Award calculator estimates an unfair dismissal award, covering the basic award and a range for the compensatory award, using the 2026 caps.

Time Limits and ACAS Early Conciliation

In Great Britain, an unfair dismissal claim must reach an employment tribunal within three months less one day of the effective date of termination where that date is before 1 October 2026, and within six months less one day where it is on or after 1 October 2026. The six-month limit comes from section 152 of, and Schedule 12 to, the Employment Rights Act 2025, brought into force on 1 October 2026 by SI 2026/954. Northern Ireland keeps a three-month limit (see below). Before filing, the employee must first notify ACAS and go through Early Conciliation, which is mandatory for most tribunal claims and pauses the clock while conciliation is attempted. Missing the deadline, even by a day, usually means the tribunal has no power to hear the claim, so anyone intending to claim should contact ACAS well before the applicable window closes. There is no fee to bring a claim, following the Supreme Court's ruling in R (UNISON) v Lord Chancellor [2017] UKSC 51, which struck down the previous fee regime. For a fuller look at the process itself, including the time-limit extension, see our guide to the employment tribunal.

Northern Ireland: A Separate but Similar Framework

Northern Ireland legislates unfair dismissal separately from Great Britain, through its own employment legislation, the Employment Rights (Northern Ireland) Order 1996, which is similar in substance but has a different qualifying period: one year's continuous service rather than two. Claims are heard by the Industrial Tribunal (and, for religious or political discrimination, the Fair Employment Tribunal) rather than the Employment Tribunal. Before claiming, you must notify the Labour Relations Agency (LRA) for early conciliation; the LRA is an advice and conciliation body that plays the role ACAS has in Great Britain. An unfair dismissal claim in Northern Ireland must be presented within three months beginning with the effective date of termination; the six-month limit that applies in Great Britain from 1 October 2026 does not apply in Northern Ireland. NI legislates separately and may not adopt the same timetable as the 1 January 2027 qualifying-period change; anyone employed in Northern Ireland should check current rules directly with the LRA rather than assume the GB reform date applies.

For the full picture of UK employment rights, see our UK employment law hub, part of our wider guide to United Kingdom law.

This article is general information about unfair dismissal law in the UK, with the Northern Ireland differences noted above, not legal advice. Employment law changes, and individual circumstances vary; consult ACAS, Citizens Advice, or a qualified solicitor before acting on your specific situation.

Frequently Asked Questions

How long do I need to work somewhere before I can claim unfair dismissal?

In Great Britain, currently two years' continuous service, falling to six months from 1 January 2027 under the Employment Rights Act 2025 (in Northern Ireland the qualifying period is one year). Automatically unfair reasons such as whistleblowing need no qualifying service at all, and a discrimination claim under the Equality Act 2010 does not depend on the qualifying period either.

Is unfair dismissal becoming a day-one right in 2027?

No. The 2027 change shortens the qualifying period to six months; it does not remove it. Employees with less than six months' service will generally still be unable to bring an ordinary unfair dismissal claim, unless their dismissal falls within an automatically unfair, day-one category.

What are the five fair reasons for dismissal?

Capability or qualifications, conduct, redundancy, statutory restriction, and some other substantial reason (SOSR). An employer must show the real reason fits one of these categories and that it followed a fair process, or the dismissal is likely to be unfair.

Can I be dismissed unfairly even if the employer had a fair reason?

Yes. A fair reason alone is not enough; the employer must also follow a reasonable procedure, generally an investigation, a hearing, and a right of appeal. A fair reason combined with an unfair process can still lead to a finding of unfair dismissal.

What compensation can I get for unfair dismissal?

A basic award, calculated using the statutory redundancy formula and capped at a £751 week's pay and 20 years' service, plus a compensatory award for actual financial loss. The compensatory award is currently subject to a statutory cap, which is removed where the effective date of termination is on or after 1 January 2027.

How long do I have to bring a claim?

In Great Britain, three months less one day from the effective date of termination (usually your last day of employment) where that date is before 1 October 2026, and six months less one day where it is on or after 1 October 2026, after first going through mandatory ACAS Early Conciliation, which pauses the clock. In Northern Ireland the limit stays at three months, after early conciliation with the Labour Relations Agency. Missing the deadline usually means the tribunal cannot hear the claim.

Does Northern Ireland have the same qualifying period?

No. Northern Ireland has its own unfair dismissal legislation, under which the qualifying period is one year's continuous service, and claims are heard in the Industrial Tribunal rather than the Employment Tribunal. NI legislates separately and may not adopt the same 1 January 2027 timetable as Great Britain, so check current rules with the Labour Relations Agency.

Do I need two years' service if I was dismissed for whistleblowing?

No. Dismissal for whistleblowing, along with pregnancy or maternity, trade union activity, and asserting a statutory right, is automatically unfair from day one and needs no qualifying period. A discriminatory dismissal can also be challenged without two years' service, as a separate claim under the Equality Act 2010.

Is there a legal minimum or maximum length for a probation period?

No. There is no statutory probation period in Great Britain: Acas confirms there is no legal requirement to have one and it can be any length, and the Employment Rights Act 2025 does not change that. What changes is the unfair dismissal qualifying period, which falls to six months from 1 January 2027. From then, an employee with more than six months' service has unfair dismissal protection even if their probation has not yet ended. Other protections, such as those against discrimination and whistleblowing detriment, apply throughout probation regardless of length of service.