How long warnings stay on your record

There is no legal time limit. Acas guidance says the period a warning stays live should be set in the employer’s disciplinary procedure, and its examples are up to six months for a first written warning and 12 months for a final written warning (longer only in exceptional circumstances). The Acas Code says you should be told how long your warning will remain current, so the answer should be in the warning letter.

What the Acas Code says

The Code covers warnings in a few lines. A first or final written warning should set out what the misconduct or poor performance was and what has to change, with a timescale. It should also say how long the warning will remain current, and what could happen if there is further misconduct within the period after a final warning, such as dismissal or demotion.

Acas treats the length as something a workplace decides when it writes its procedure. Its guide says that, except in agreed special circumstances, disciplinary action should be disregarded after a specified period of satisfactory conduct or performance. The guide’s model letter has a blank for the number of months, and says the warning is placed on the personal file but disregarded for disciplinary purposes after that time, provided conduct or performance improves.

Typical periods

Type of warning	Acas example
First written warning	up to six months
Final written warning	12 months, or more in exceptional circumstances

These are examples of normal practice, not rules. A public sector employer might use different figures, so check your own employer’s disciplinary or capability policy and the wording of your warning letter. The disciplinary procedures guide explains the stages that lead to each warning.

What happens when a warning expires

Acas says warnings should stop being live after the specified period of satisfactory conduct. In practice that has three effects.

A decision to dismiss should not be based on an expired warning. If you get a new warning or face a new allegation, the earlier one should not count as a live step towards dismissal.

An expired warning can still be mentioned. Acas says it may explain why the employer does not choose a lesser sanction. Say you are accused of a new offence of a similar kind. The employer may point out that you have had the earlier warning when deciding what outcome is fair, even though it no longer counts as live.

The record itself can stay. Acas says a record of the warning should be kept but disregarded for disciplinary purposes after the specified period. If you want to know whether it is retained, you can ask HR, and you can use a subject access request. The subject access guide explains how.

Satisfactory conduct and timing

The expiry depends on satisfactory conduct or performance during the period. The Acas guide notes that conduct can be fine while a warning is live and slip soon after it lapses. Where a pattern like that emerges, it says, the employee’s disciplinary record should be borne in mind when deciding how long a warning should last. So a record with repeated warnings can lead to a longer period on the next one. If a further issue is raised while you are on a warning, ask for the exact expiry date in writing and check it against the warning letter.

Informal conversations are different from formal warnings. The NHS pay step rules, for example, only count formal conduct sanctions and not informal warnings or counselling, which is covered in the NHS disciplinary procedure guide. A live sanction can delay a pay step, so the expiry date also controls when it can move.

Warnings and references

A warning that has expired is not the same as one that never happened. Whether your employer mentions it in a reference is a separate question, and the references guide covers what employers can say about you.

If you think the dates are wrong

Start with the warning letter and the policy. If you think the warning itself was wrong, the Acas Code says you should have the chance to appeal, with your grounds set out in writing. If the letter does not say how long the warning lasts, point out that the Acas Code expects it to, and ask in writing for the date. If it is not resolved, you can raise a grievance, speak to your union representative, or ring the Acas helpline.