How to discipline an employee fairly in the UK (ACAS step-by-step)
When an employee's conduct or performance falls short, how you handle it matters as much as the decision itself. Most unfair-dismissal claims aren't lost on the facts — they're lost because the employer skipped a fair process. UK tribunals expect you to follow the ACAS Code of Practice on Disciplinary and Grievance Procedures.
The five steps of a fair disciplinary process
1. Investigate first. Establish the facts before forming a view. Gather evidence and speak to anyone involved. Suspension should be rare, on full pay, and treated as a neutral act — not a punishment.
2. Put it in writing. If there's a case to answer, write to the employee setting out the concern clearly and inviting them to a disciplinary meeting. Include any evidence so they can prepare.
3. Hold the meeting. Explain the concern, share the evidence, and give the employee a genuine chance to respond. By law they can be accompanied by a colleague or trade-union representative.
4. Decide proportionately. Choose an outcome that fits — anything from no action or a first written warning, through to a final written warning or, in serious cases, dismissal. Confirm it in writing with reasons.
5. Offer a right of appeal. Always. Ideally the appeal is heard by someone not previously involved.
What counts as gross misconduct?
Gross misconduct (theft, fraud, violence, serious safety breaches) can justify dismissal without notice — but you must still investigate and hold a hearing. "Obvious" cases are exactly where employers trip up by cutting corners.
Keep records
Document every step: the investigation, the invite, notes from the meeting, the decision and the appeal. If your decision is ever challenged, those records are your best defence.
This is a high-risk area, so a tested process and the right letters make all the difference. Our Disciplinary & Grievance kit gives you the full ACAS-aligned procedure plus every letter you'll need.
Handling a difficult employee? Get the ACAS-aligned process and every letter.
Get the kit →This guide is general information, not legal advice. For significant or contentious matters, seek advice from a qualified employment-law professional or ACAS (0300 123 1100).