What is the ACAS Code on disciplinary procedures?

What the ACAS Code is

The ACAS Code of Practice on Disciplinary and Grievance Procedures is the UK's foundational statement on fair process at work. Issued by the Advisory, Conciliation and Arbitration Service under section 199 of the Trade Union and Labour Relations (Consolidation) Act 1992, it sets the minimum steps a fair employer should follow when handling discipline, dismissal, or grievance.

It runs to about 30 paragraphs. Almost every UK unfair dismissal case turns on whether it was followed.

Why following it matters

The Code is not directly enforceable — you can't sue an employer just for breaching the Code itself. But tribunals must take it into account in any disciplinary or grievance dispute. Two specific consequences under section 207A of the 1992 Act:

• Up to a 25% increase in compensation if the employer unreasonably failed to follow the Code
• Up to a 25% reduction if the employee unreasonably failed to follow it

A dismissal carried out in breach of the Code can also be procedurally unfair in its own right — meaning even if the underlying reason justified termination, the dismissal is unfair because of how it was done.

The arithmetic is unforgiving. A £30,000 unfair dismissal award uplifted by 25% becomes £37,500. Skipping the appeal stage to save a meeting can cost £7,500.

The six core steps

The Code's structure for disciplinary cases:

1. Investigate

Establish the facts before formal action. The investigation should be:

• Proportionate to the seriousness of the alleged conduct
• Carried out promptly (memory and evidence fade)
• Conducted by someone other than the eventual decision-maker (so the decision-maker isn't pre-conditioned)
• Documented — investigation notes, witness statements, evidence preserved

For minor issues, a brief manager-led inquiry. For serious allegations, a structured investigation by HR or an independent investigator.

2. Inform the employee in writing

Before the hearing, the employee must receive a written statement that includes:

• The specific allegation — what they're alleged to have done
• The evidence the employer relies on (witness statements, copies of relevant policies, records)
• The possible outcomes — including the possibility of dismissal where relevant
• The date, time, and location of the hearing
• Their right to be accompanied

A vague or shifting allegation undermines the employee's ability to respond and is a frequent ground for unfair dismissal findings.

3. Hold a hearing

The hearing should be a genuine opportunity for the employee to respond. Run it:

• Promptly but with sufficient notice for the employee to prepare (typically 5–7 working days)
• Privately, away from open-plan office areas
• With someone taking notes (not the chairperson)
• Without unfair time pressure — the employee should be able to make their full case
• Allowing questions — the employee should be able to challenge the evidence and witnesses

The employee's right to be accompanied is statutory under section 10 of the Employment Relations Act 1999. They can bring a trade union representative or fellow worker. Refusing the right is itself a breach with separate compensation of up to two weeks' pay.

4. Decide and communicate

After the hearing, the decision-maker considers the evidence, the employee's response, and previous similar cases. The decision should be:

• Reasonable — the sanction proportionate to the conduct
• Consistent with how similar cases have been handled before
• Communicated in writing — including the reasoning, the sanction, and the right of appeal

A typical disciplinary outcome ladder:

• No formal action — informal feedback, coaching
• Verbal warning — recorded, lasts a defined period (often 6 months)
• Written warning — formal, lasts a defined period (often 12 months)
• Final written warning — typically lasts 12 months, often a precondition for dismissal
• Dismissal — with notice, or without notice for gross misconduct

5. Allow an appeal

Every disciplinary decision must come with a right of appeal — typically to a more senior manager who hasn't been involved in the original decision. The appeal:

• Must be heard promptly
• Must be a genuine reconsideration, not a rubber-stamp of the original decision
• Should give the employee a chance to make their case again, with any new evidence
• Should result in a written outcome — confirmed, varied, or overturned

Skipping or sidelining the appeal stage is one of the most common Code failures.

6. Apply consistently

Sanctions should be consistent with previous cases. If two similar offences received different outcomes, the employer needs a clear and defensible reason — otherwise the inconsistency itself becomes a discrimination or unfair dismissal point.

This means keeping records of past disciplinary actions and their outcomes, and consulting them when deciding new cases.

Conduct vs capability — same shape, different content

The Code applies to both conduct and capability issues, but the substance differs:

• Conduct issues are about choices the employee made — breaking rules, dishonesty, poor attendance without good reason. The process focuses on what they did and whether it warrants the sanction.
• Capability issues are about ability — skills gaps, performance shortfalls, ill health. The process typically includes more support and improvement steps before any disciplinary outcome.

A capability process for performance shortfalls usually involves:

1. Discussion identifying the gap
2. Improvement plan with specific objectives and a timeframe
3. Regular reviews during the improvement period
4. Final review — confirm, extend, or move to formal action
5. Final warning if performance hasn't improved
6. Dismissal if performance still hasn't improved after warning

The same Code shape applies, but with the support phase built in.

Gross misconduct

Some conduct is so serious it can justify summary dismissal — dismissal without notice or pay in lieu — for a first offence. Common examples in employee handbooks:

• Theft, fraud, or deliberate falsification
• Serious or wilful breach of health and safety
• Serious harassment, bullying, or discrimination
• Being under the influence of drugs or alcohol at work
• Wilful damage to property
• Serious breach of confidentiality

Even for gross misconduct, the ACAS Code still applies. The most common reason gross misconduct dismissals are found unfair is that the employer skipped steps because the case "seemed obvious" — no investigation, no proper hearing, no appeal.

Suspension during investigation

If the employer needs to remove the employee from the workplace during investigation, they can suspend on full pay. Suspension:

• Should be on full pay unless the contract clearly permits otherwise
• Should be for the shortest practicable time
• Should be communicated in writing with reasons
• Is a neutral act — not a disciplinary sanction, and shouldn't prejudice the outcome

Holding someone on extended suspension while the investigation drifts is a frequent breach of trust and confidence — and a potential constructive dismissal claim.

Alternative outcomes

Disciplinary issues don't always end with a sanction. Other options include:

• Mediation — particularly for interpersonal disputes
• Training or coaching — for skills or knowledge gaps
• Settlement agreement — for negotiated exit on agreed terms
• No further action — where the investigation finds the allegation unfounded

Considering and documenting these alternatives — not just leaping to discipline — strengthens the employer's process.

Records to keep

For every disciplinary case, retain:

• The investigation evidence and notes
• The notification letter and meeting invitation
• Hearing notes and any submitted documents
• The decision letter
• Any appeal correspondence and outcome
• The duration of any warning under the policy

UK GDPR retention principles apply: typically until the warning expires plus 12 months, then routine deletion.

Common Code failures

Skipping investigation

"It's obvious what happened" — but tribunals will need to see the steps taken to verify. Without investigation, there's no defensible factual base.

Decision-maker also investigated

The same person who gathered the evidence shouldn't be the one deciding the outcome. Pre-conditioning is hard to argue against.

Vague allegation in the notification

"Conduct issues" or "performance concerns" aren't specific enough. The employee must know exactly what they're answering to.

Denying the right to be accompanied

A statutory right. Refusing it has its own compensation award.

Treating appeal as a formality

The appeal must be a genuine reconsideration. If the appeal letter just rubber-stamps the original decision word-for-word, tribunals notice.

Inconsistent sanctions

Different outcomes for similar cases — without a defensible reason — is itself a Code breach.

Putting it into practice

A robust disciplinary process:

1. Triggers a written allegation only after preliminary fact-finding
2. Separates the investigator from the decision-maker
3. Gives the employee written notice of the hearing with at least 5 working days' notice
4. Documents the hearing and the deliberation
5. Issues a written decision with clear reasoning and the right of appeal
6. Hears the appeal with a genuinely fresh decision-maker
7. Maintains a consistent record of past sanctions for comparability

The ACAS Code is short, clear, and freely available. Reading it once is the cheapest legal investment a UK employer can make. Almost every unfair dismissal case is, at root, a Code-following case.