Unfair dismissal in Great Britain when AI data is behind the decision

More employers now hold performance scores, productivity figures and conduct flags produced by software. When one of those numbers leads to a dismissal, the ordinary law of unfair dismissal applies: there is no separate rule for AI. This page sets out, for workers and employers in England, Wales and Scotland, the parts of the Employment Rights Act 1996 that decide such cases, as the text stood on 31 October 2026. Northern Ireland has separate legislation.

The short answer: an employee with enough service has the right not to be unfairly dismissed. The employer must show the real reason, such as capability or conduct, and the tribunal then asks whether it acted reasonably in treating that reason as enough to dismiss. A software score is evidence, not a reason in itself, so the employer needs to be able to show what the score measured, that it was accurate, and that the employee had a fair chance to answer it.

Who can claim

• The right: an employee has the right not to be unfairly dismissed by their employer (section 94). Workers and the self-employed do not have this right; see employee, worker or self-employed.
• Qualifying period: the right generally applies only after 2 years of continuous employment ending with the effective date of termination (section 108(1)). The Employment Rights Act 2025 will replace "two years" with "six months" (2025 Act, section 25(2)), with effect from 1 January 2027, where the effective date of termination is on or after that date (SI 2026/559, regs 3(a) and 4). Until then, 2 years applies.
• No qualifying period for some reasons: section 108(3) lists reasons where the 2 year rule does not apply, including dismissal for making a protected disclosure (section 103A) and for asserting a statutory right (section 104). Health and safety reasons are also on the list; see raising safety concerns. See UK whistleblowing law and AI and, for the EU rules, raising concerns about AI at work.
• Discrimination is separate: the qualifying period applies to the unfair dismissal right, not to claims under the Equality Act 2010. If a tool may have treated someone worse because of a protected characteristic, see AI and the Equality Act 2010.
• Resigning can count as dismissal: an employee who ends the contract because the employer's conduct entitles them to leave without notice is treated as dismissed (section 95(1)(c)); see constructive dismissal and AI.

The employer must show a fair reason

It is for the employer to show the reason, or the principal reason, for the dismissal and that it is a potentially fair one (section 98(1)). The reasons in section 98(2) include that it relates to the employee's capability or qualifications for the work, or to their conduct, as well as redundancy and a legal bar on continuing in the job. Where a tool helps pick who is made redundant, see AI and redundancy selection in Great Britain, and for the payment, statutory redundancy pay. Capability means capability assessed by reference to skill, aptitude, health or any other physical or mental quality (section 98(3)).

For AI data this matters in practice. "The system ranked you in the bottom 10%" is not, on its own, a reason in section 98(2). The employer has to link the number to something the law recognises: that the person could not do the work to the required standard (capability), or that they did something wrong (conduct). If the score measures something else, such as keyboard activity rather than output, that link may be hard to show.

Did the employer act reasonably?

Once a fair reason is shown, whether the dismissal was fair depends on whether, in the circumstances, including the size and administrative resources of the employer, it acted reasonably or unreasonably in treating that reason as sufficient. The question is decided in accordance with equity and the substantial merits of the case (section 98(4)). Points that commonly bear on that question when software data is involved:

• whether the employer checked the data was accurate and complete, and understood what it measured;
• whether the employee saw the evidence and had a real chance to explain it, for example time lost to system faults, other duties or a disability;
• whether a person with authority looked at the whole picture before deciding, rather than following the score;
• whether a capability issue was raised early, with support and time to improve, before dismissal was considered.

Where a decision about a worker is based solely on automated processing with significant effects, UK data protection law adds its own safeguards, including the right to human intervention and to contest the decision; see automated decisions at work under UK law. For the rules on collecting monitoring data in the first place, see employee monitoring rules in the UK.

Procedure: the Acas Code, a companion and written reasons

• Acas Code of Practice: in claims covered by the rules, if an employer unreasonably fails to follow a relevant Code of Practice on dispute procedures, such as the Acas Code on disciplinary and grievance procedures, the tribunal may increase the award by up to 25%. An employee's unreasonable failure can reduce it by up to 25% (Trade Union and Labour Relations (Consolidation) Act 1992, section 207A).
• Right to be accompanied: a worker invited to a disciplinary hearing who reasonably asks to be accompanied may bring one companion, a trade union official or a colleague, who can put and sum up the worker's case (Employment Relations Act 1999, section 10).
• Written reasons: an employee with 2 years' service who asks for a written statement of the reasons for dismissal must be given one within 14 days (section 92). Asking for one is a simple way to find out whether a score or flag played a part. You can also ask for your personal data, including the data a system used; see how to request the data AI systems hold on you.

Time limit

A complaint must reach an employment tribunal within 6 months beginning with the effective date of termination, or within a further reasonable period if bringing it in time was not reasonably practicable (section 111(2)). The 6 month limit applies where the effective date of termination is on or after 1 October 2026; for earlier dismissals the limit was 3 months (S.I. 2026/954, regulations 3 and 4). The limit can be extended to allow for Acas early conciliation (section 111(2A)). Seek advice early.

Practical steps for employers

• Know what each tool measures, how accurate it is, and how it treats absence, part time work and adjustments. Do not let a score stand in for a reason.
• Share the data with the employee before any decision, and record their explanation and what you did to check it. For the meeting itself, see the Acas Code and the right to be accompanied.
• Follow the Acas Code and your own capability or disciplinary procedure, and keep a named manager responsible for the outcome.
• Check the outcomes of scoring tools for different groups; see AI in performance reviews.

For employees

If you are told a score, ranking or monitoring flag is the reason for a warning or dismissal, ask which system produced it, what data it used and for what period, and whether anyone checked it. Point out anything the data misses. Bring a companion to the hearing, ask for written reasons, note the date your employment ends and keep the time limit in mind. This page is general information, not legal advice.