What are the key principles of the ACAS disciplinary procedure?

The ACAS Code requires employers to investigate and establish the facts, inform the employee of the allegation in writing with evidence, hold a fair meeting with at least 48 hours notice, allow the employee to be accompanied by a trade union rep or colleague, decide and confirm the outcome in writing, and offer a right of appeal.

What are the stages of a disciplinary procedure?

The typical stages are an informal conversation for minor issues, a first written warning (usually kept on record for 6 months), a final written warning (usually active for 12 months), and dismissal — with notice for continued failure to improve, or summary dismissal without notice for gross misconduct.

What counts as gross misconduct?

Examples of gross misconduct include theft, fraud, physical violence, serious health and safety breaches, being under the influence of drugs or alcohol at work, and serious insubordination. These may justify summary dismissal without previous warnings.

ACAS disciplinary procedure: what UK employers must know

What is the ACAS Code of Practice?

ACAS (Advisory, Conciliation and Arbitration Service) publishes a Code of Practice on Disciplinary and Grievance Procedures. While not legally binding, employment tribunals are required to take it into account. If an employer unreasonably fails to follow the Code, tribunal awards can be increased by up to 25%.

The key principles

The ACAS Code requires that employers:

Investigate - establish the facts before taking action
Inform in writing - tell the employee what the allegation is and provide evidence
Hold a meeting - give the employee a fair hearing with at least 48 hours' notice
Right to be accompanied - the employee can bring a trade union rep or colleague
Decide and communicate - make a decision and confirm it in writing
Right of appeal - the employee must be able to appeal the decision

The stages of a disciplinary procedure

Informal stage

For minor issues, ACAS recommends starting with an informal conversation. Document the discussion and agreed actions but don't add it to the formal record.

First written warning

If the issue continues or is more serious, issue a first written warning. This typically remains on the employee's record for 6 months.

Final written warning

For continued misconduct or a more serious incident, issue a final written warning. This typically remains active for 12 months.

Dismissal

Dismissal (with notice) for continued failure to improve, or summary dismissal (without notice) for gross misconduct.

Which letter to send at each stage

Every formal step in the Code is confirmed in writing. The free letter templates below follow the Acas Code and are readable in full, with a PDF download and no signup:

Stage	What must be in writing	Free template
Invitation to a disciplinary hearing	The allegation, the evidence, the possible outcome (say so if dismissal is possible), the date, and the right to be accompanied	Disciplinary hearing invitation letter
Outcome: warning or dismissal	The decision, the reasons, how long a warning stays live, what improvement is expected, and the right of appeal	Disciplinary outcome letter
Poor performance rather than conduct	Handled under a capability procedure, with the same fair-hearing steps	Capability policy
Grievance raised by the employee	Invitation to a grievance meeting, then a written outcome with the right of appeal	Grievance meeting invitation · Grievance outcome letter
The procedure itself	A written disciplinary policy every employee has been given	Disciplinary policy · Grievance policy
Record of the hearing	Who attended, the evidence put and the employee's replies; Acas advises keeping a written record of every case	Disciplinary hearing notes template
First or final written warning	The misconduct or poor performance, the improvement required and by when, how long the warning stays current, the consequence of not improving after a final warning, and the right of appeal	Written warning letter template (first & final)
Dismissal, with or without notice	The reasons, the date employment ends, the notice period, and the right of appeal	Dismissal letter template
Appeal against the decision	The employee's grounds of appeal, then the result of the appeal hearing as soon as possible	Disciplinary appeal letter template
Invitation to a capability hearing	The performance concern, the evidence, the possible outcome (say so if dismissal is possible), the date, and the right to be accompanied	Poor-performance (capability) hearing invitation letter

Examples of gross misconduct

Theft, fraud, physical violence, serious H&S breaches, being under the influence of drugs/alcohol at work, serious insubordination. These may justify summary dismissal without previous warnings.

Why documented policies matter

In an unfair dismissal claim, the tribunal will ask:

Did the employer have a written disciplinary policy?
Was the employee made aware of it?
Did the employer follow its own procedure?
Did the employer follow the ACAS Code?

If the answer to any of these is “no”, the employer's position is significantly weakened - and awards can be increased by 25%.

How TrainedTeam helps

Ready-made template - our Disciplinary Policy template follows the structure recommended in the ACAS Code of Practice
E-signatures - prove the employee received and acknowledged the policy
Version tracking - know which version of the policy was in place when an incident occurred
Training verification - show managers completed training on how to follow the procedure

ACAS Disciplinary Procedure: what UK employers must know