Definition
A formal disciplinary sanction issued to an employee following a finding of misconduct or poor performance. A first written warning is typically the second stage of a disciplinary process, after an informal warning or verbal warning.
UK Context
The ACAS Code of Practice recommends a graduated disciplinary process that includes written warnings. While the Code is not legally binding, employment tribunals must take it into account, and failure to follow it can result in an uplift of up to 25% on compensation awards. Written warnings should be time-limited — typically 6-12 months.
Best Practices
- Always hold a formal disciplinary hearing before issuing a written warning, even for minor matters
- Set a clear duration for the warning — typically 6-12 months — and remove it from active consideration once expired
- Include specific improvement targets and timescales so the employee knows exactly what is expected
- Offer the right to appeal in the warning letter, with a clear deadline and named appeal contact
Frequently Asked Questions
How long does a written warning last?
Most employers set a duration of 6-12 months for a first written warning. After this period, the warning is considered 'spent' and should not normally be used as the basis for further disciplinary escalation. However, it remains on the personnel file as a historical record.
Can an employee be given a written warning without a hearing?
No. The ACAS Code of Practice requires that an employee is notified of the allegations and given the opportunity to respond at a formal hearing before any disciplinary sanction is imposed. Issuing a warning without a hearing is a procedural deficiency that could be challenged.
Does a written warning affect future employment references?
Expired warnings should not normally be mentioned in references. However, a live warning at the time the reference is given may be disclosed, particularly if the reference covers conduct or performance. Employers should have a clear references policy.