Grievance Procedure: A Step by Step Guide for UK Employers

If you run a UK business with staff, a formal grievance will land on your desk sooner or later. How you handle the first 48 hours sets the tone for everything that follows, including any tribunal claim.

This is a step by step grievance procedure from the employer side. It follows the Acas Code of Practice on Disciplinary and Grievance Procedures, which tribunals use to judge whether you behaved reasonably. Get it right and you cap your risk. Get it wrong and tribunals can increase compensation by up to 25% for unreasonable failure to follow the Code.

What is a grievance and why the procedure matters

A grievance is a concern, problem or complaint that an employee raises with their employer. It covers everything from a pay dispute to bullying allegations, rota changes to whistleblowing disclosures.

The legal backbone is Section 207A of the Trade Union and Labour Relations (Consolidation) Act 1992, which gives the Acas Code its teeth. Tribunals must take the Code into account and can adjust awards by up to 25% either way for unreasonable failure to follow it.

Beyond the legal exposure, a well run procedure:

• Catches problems before they become constructive dismissal claims
• Creates a paper trail if matters escalate
• Signals to the workforce that complaints are taken seriously
• Often resolves the issue at stage one without any formal meeting

When the grievance procedure applies

Your written procedure should cover any concern not suitable for an informal chat. Typical examples:

• Pay, hours, holiday or contractual terms
• Working conditions and health and safety
• Bullying, harassment or discrimination
• Relationships with managers or colleagues
• Reorganisation or changes to working patterns
• Equality Act issues including reasonable adjustments
• Whistleblowing under the Public Interest Disclosure Act 1998

Since April 2026, sexual harassment is a qualifying whistleblowing disclosure under the Employment Rights Act 2025. The person raising it gets whistleblower protection as well as grievance rights. If in doubt, treat it as both.

The Acas grievance procedure: five stage summary

The Acas Code boils down to five practical stages. Your written policy should mirror these steps with your own timelines and named roles.

1. Informal resolution where appropriate
2. Formal written grievance submitted by the employee
3. Grievance meeting without unreasonable delay
4. Written outcome with decision and reasons
5. Right of appeal to a different decision maker

Work through each stage in order. Skipping steps is the single most common reason tribunals find against employers on procedural grounds.

Stage 1: Try informal resolution first

Most workplace issues are better fixed with a conversation. Line managers should be trained to listen, ask what outcome the employee wants and try to resolve it on the spot.

Informal resolution is not brushing it under the carpet. Document the conversation, note what was agreed and follow up in writing. If the issue is serious (harassment, discrimination, whistleblowing), skip informal and go formal.

Do not force an employee to try informal resolution before a formal grievance. The Code requires you to deal with grievances formally when raised formally.

Stage 2: Receiving a formal grievance

A formal grievance must be in writing. Your policy should set out where to send it, usually to the line manager, or to HR if the grievance is about the line manager.

Acknowledge the grievance in writing within 5 working days. Confirm:

• That you have received it
• Who will be investigating
• Approximate timeline to a meeting
• The employee's right to be accompanied at any grievance meeting

Do not investigate in silence. Employees who hear nothing assume the worst and often escalate to solicitors before you have even read the letter.

Choose the right decision maker

The person hearing the grievance should be senior enough to make binding decisions and independent enough to be objective. Never have someone investigate a grievance about themselves. For small employers with no alternative, bring in an external HR consultant.

You will need a separate, more senior person to hear any appeal. Plan this in advance.

Stage 3: Investigate properly

The investigation gathers facts. The meeting gives the employee a chance to explain their case and hear your preliminary findings. They are not the same thing.

Investigation steps:

• Interview the employee who raised the grievance
• Interview any named witnesses
• Review relevant documents: contracts, emails, rotas, CCTV, performance records
• Check policy against practice
• Keep contemporaneous notes of every interview

Witnesses should be told their account will be shared with the complainant unless there is a genuine risk of victimisation. Anonymous witness statements are a tribunal red flag.

Stage 4: Hold the grievance meeting

The grievance meeting is where the employee states their case in person, with the investigating manager present.

Timing

Hold the meeting "without unreasonable delay". Two to three weeks from receipt is a reasonable benchmark. Complex cases may justify longer, but communicate the delay in writing with reasons.

Right to be accompanied

Under Section 10 of the Employment Relations Act 1999, every worker has a statutory right to be accompanied by a trade union representative or a fellow worker. Postpone by up to five working days if the chosen companion cannot attend. See our right to be accompanied guide for detail.

How to run the meeting

• Introduce everyone and explain the format
• Invite the employee to set out their grievance in their own words
• Ask clarifying questions, do not cross examine
• Allow the companion to sum up and speak on the employee's behalf, but not to answer questions for them
• Summarise the points raised and confirm next steps
• Adjourn if new information needs further investigation

Take detailed notes and offer the employee a copy for corrections on factual points.

Stage 5: The written outcome

Communicate the decision in writing, usually within 5 to 10 working days of the meeting. The outcome letter should cover:

• A summary of the grievance raised
• The investigation steps taken
• The findings on each specific complaint
• The decision: grievance upheld, partially upheld, or not upheld
• Any actions to be taken (training, mediation, policy change, apology)
• The right of appeal, including who to appeal to and the deadline (typically 5 to 7 working days)

Avoid vague conclusions like "matters have been addressed". Tribunals want to see that you reached a reasoned decision on each specific point raised.

Stage 6: The appeal

Hear the appeal at a more senior level. This is the last internal chance to fix a flawed decision before a tribunal claim.

Two formats are acceptable:

• Review appeal: the appeal manager reviews the existing evidence
• Rehearing: the entire grievance is heard afresh with new fact finding

The rehearing format is safer where the original procedure was flawed. A rehearing can cure procedural defects. A review cannot.

The employee retains the right to be accompanied at the appeal meeting. Confirm the outcome in writing and state clearly that this is the final stage of the internal procedure.

Grievance procedure timeline at a glance

• Day 0: Written grievance received
• Within 5 working days: Written acknowledgement
• 1 to 3 weeks: Investigation
• Within 2 to 3 weeks: Grievance meeting
• Within 5 to 10 working days of meeting: Written outcome
• Within 2 to 3 weeks of appeal letter: Appeal heard
• Within 5 to 10 working days of appeal: Appeal outcome

These are not statutory timelines. They are reasonable benchmarks tribunals recognise as compliant with the Code.

Special cases employers trip up on

Grievances raised during disciplinary action

Employees often raise a grievance as a defensive tactic when they are in a disciplinary process. The Acas Code allows you to:

• Pause the disciplinary and deal with the grievance separately, or
• Deal with both concurrently if they are related

Whichever route you choose, document it. If you run concurrent procedures, make sure different people hear each one. For the companion disciplinary side of this, see our disciplinary procedure employer guide.

Grievances from someone who has resigned

A post-resignation grievance is still a grievance. Handle it through the normal procedure, even if the employee has already left. Failing to do so is a classic trigger for constructive dismissal claims and is almost always cited in the tribunal pleading. See constructive dismissal: an employer guide for how resignation and grievance interact.

Collective grievances

Where multiple employees raise the same grievance, allow them to raise it jointly through a spokesperson. Investigate once, meet the spokesperson and issue one outcome, with a copy for each employee.

Anonymous grievances

Anonymous complaints are not grievances under the Code because the procedure is designed for a named employee. Still assess whether they warrant a separate management investigation, particularly around safeguarding, financial or harassment concerns.

Grievances about harassment

Since October 2024, employers have had a proactive duty under the Worker Protection Act to prevent sexual harassment. From April 2026, the Employment Rights Act 2025 made sexual harassment a qualifying whistleblowing disclosure. Handle these with particular care. Confidentiality, speed and a clear paper trail matter more than in standard cases.

Common grievance procedure mistakes

The patterns that appear most often in tribunal claims:

• No written procedure or a procedure that nobody inside the business has read
• Line manager investigates a grievance about themselves
• No acknowledgement letter and weeks of silence before the first meeting
• Failure to offer the right to be accompanied in writing
• Outcome letter with no reasons, just a bare decision
• No appeal option or the same person hearing the appeal as the original grievance
• Concurrent disciplinary and grievance handled by the same manager
• Witness evidence taken but never shared with the complainant
• Ignoring grievances from people on sick leave

Each of these has led to tribunal awards being uplifted by 25%.

What to put in your written policy

Your written grievance policy should include:

• Purpose and scope
• Who to submit the grievance to, with a backup if that person is the subject
• Target timelines for each stage
• The right to be accompanied
• How the investigation will be conducted
• Decision making authority at each stage
• Appeal rights and deadline
• Confidentiality expectations
• Record retention (usually 6 years)
• Links to related policies: disciplinary, whistleblowing, bullying and harassment

Every employee should have access from day one. Put a copy in the staff handbook and reference it in the written statement of particulars issued to every new starter.

Records and retention

Keep the following for at least six years after the grievance closes: the original grievance, acknowledgement letter, investigation notes, witness statements, documents reviewed, meeting notes, outcome and appeal letters, and evidence that agreed actions were completed.

Store them securely. Grievance records are special category personal data if they touch on health, sexuality, religion or race. Process them under your GDPR records of processing activity.

What happens if the grievance becomes a tribunal claim

If the employee brings a tribunal claim, the grievance procedure is the first thing the tribunal will scrutinise. Expect the employee's legal representatives to issue a data subject access request for every document, note and email. Anything you did not share at the time can still be compelled later.

Write everything as though it will land in front of a tribunal judge. Dry, factual, dated. Avoid speculation or character judgements in emails. For the full tribunal path, see our employment tribunal process employer guide.

Grievance procedure checklist

• Written grievance received and logged
• Acknowledgement letter sent within 5 working days
• Independent investigating manager appointed
• Witnesses interviewed and notes retained
• Grievance meeting arranged with at least 5 days notice
• Right to be accompanied confirmed in writing
• Meeting notes offered to the employee
• Written outcome issued with reasons and appeal rights
• Appeal manager identified and briefed
• All records stored securely for 6 years

FAQs

Q: How long does an employer have to respond to a formal grievance in the UK?

A: There is no statutory deadline, but the Acas Code requires employers to respond "without unreasonable delay". Best practice is a written acknowledgement within 5 working days, a grievance meeting within 2 to 3 weeks and a written outcome within 5 to 10 working days of the meeting. Appeals should be heard within 2 to 3 weeks of the appeal letter. Exceeding these benchmarks without a clear reason exposes you to a 25% tribunal uplift for failing to follow the Code.

Q: Can an employee raise a grievance after they have resigned?

A: Yes. A grievance from a former employee, including one raised during their notice period or after their leaving date, should be handled under your normal procedure. Refusing to hear a post-resignation grievance is a frequent trigger for constructive dismissal claims and will almost always be cited in the tribunal pleading. Run the full procedure, including the appeal stage.

Q: Who can accompany an employee at a grievance meeting?

A: Under Section 10 of the Employment Relations Act 1999, a worker has a statutory right to be accompanied by a trade union representative (or certified union official) or a fellow worker. You cannot unreasonably refuse the chosen companion. If the first choice of companion cannot attend, the worker can propose an alternative, and you must postpone by up to 5 working days. Family members, solicitors or external HR consultants are not statutory companions, although you can permit them as a matter of policy.

Q: What happens if an employer ignores a grievance?

A: The employee can resign and claim constructive unfair dismissal on the basis that the failure to deal with their grievance was a fundamental breach of the implied term of trust and confidence. They can also bring substantive tribunal claims (for example on discrimination or unlawful deduction of wages) with a compensation uplift of up to 25% for your failure to follow the Acas Code. Ignoring grievances is one of the most expensive procedural failings an employer can make.

Q: Do we have to follow the Acas Code of Practice on grievances?

A: The Acas Code itself is not legally binding, but under Section 207A of the Trade Union and Labour Relations (Consolidation) Act 1992, tribunals must take it into account. Tribunals can adjust compensation by up to 25% either way for unreasonable failure to comply. In practice, every UK employer should treat it as mandatory baseline.

Q: Can we have both a disciplinary and grievance process running at the same time?

A: Yes. The Acas Code allows concurrent handling where the issues are related, or pausing the disciplinary until the grievance is resolved where they are separate. Whichever route you take, use different managers for each process and document the decision. Running both with the same decision maker almost always leads to a procedural challenge at tribunal.

Next steps

For a full review of your grievance procedure against the Acas Code, the Employment Rights Act 2025 changes and your actual practice, run the EmployerKit audit. It gives you a scored report on every part of your HR policy stack, with the exact wording and template updates you need to stay compliant.