Grievance procedure UK: how to raise a complaint at work

Workplace conflict can affect your mental health and job stability. If you are dealing with bullying, unfair treatment, or contract disputes, UK law provides a formal grievance procedure to protect you. This guide covers the formal grievance process, the latest legislative updates, and your workplace discrimination rights. If the situation is complex or deadlines are approaching, consider consulting an employment solicitor to understand your specific rights.

Key Takeaway: What is the formal process for raising a complaint?

To raise a formal complaint, submit your concerns in writing to your employer. They must follow a fair grievance procedure involving an investigation, a formal hearing, and a written decision.

You have a statutory right to be accompanied by a colleague or trade union representative, and you must be given the opportunity to appeal the outcome if you are unhappy with it.

The Acas code of practice on disciplinary and grievance procedures

The Acas code of practice is the UK framework for resolving workplace disputes. While not a law, Employment Tribunals use this statutory framework to judge whether an employer acted reasonably.

Failing to follow the code may carry significant financial consequences at a tribunal:

• Employer failure: Your compensation may be increased by up to 25%.
• Employee failure: Your compensation may be reduced by up to 25%.

Step 1: Attempting to resolve a grievance at work informally

Before raising a formal grievance, Acas suggests trying informal resolution first to save time and preserve working relationships. This is especially important in cases involving workplace bullying or harassment, where early action can prevent escalation:

• Initial meeting: Request a private discussion with your line manager to explain your concerns and propose a solution.
• Alternative contact: If your complaint involves your manager, speak to another manager or HR.
• Mediation: Ask for a neutral third party to facilitate the conversation if a direct talk is too difficult.
• Timeline: Informal resolution is usually quick, typically taking 1 to 5 days.

Step 2: How to launch an employee grievance procedure formally

If informal talks fail or the matter is too serious, start a formal grievance by submitting a written complaint to your manager, or an alternative contact like HR if your manager is involved. Check your staff handbook or intranet for your employer’s specific policy.

Your letter must include:

• A clear description of the problem.
• Key dates and times of the incidents.
• Names of any witnesses involved.
• The outcome or solution you are seeking.

Step 3: The investigation phase and evidence gathering

Once the formal grievance is received, the employer must investigate the facts. This stage should be conducted thoroughly and objectively by someone who is not involved in the case.

Timeliness:

Investigations typically take 5 to 15 working days, although complex cases may take longer. Your employer should keep you informed of any delays.

Step 4: Attending the formal grievance hearing

The formal hearing is your opportunity to explain your grievance in detail. Your employer must arrange this without unreasonable delay after the investigation.

Right to be accompanied

Under UK law, you have a statutory right to bring a companion:

• Who to bring: A work colleague or a trade union representative.
• Their role: They can address the hearing, sum up your case, and confer with you, but they cannot answer questions on your behalf.

Step 5: Receiving a decision and understanding your right to appeal

Following the hearing, your employer must provide a written decision detailing any intended actions. If you are unsatisfied, you have the right to appeal. Under the Acas code:

• Written appeal: You must submit your grounds for appeal in writing.
• Appeal meeting: A meeting should be held, ideally led by a more senior manager who was not previously involved.
• Companion: You retain your statutory right to be accompanied at this meeting.

Constructive dismissal and the Employment Rights Act 2025

An unresolved grievance may trigger a constructive dismissal claim if your employer’s behaviour breaches the implied term of trust and confidence in your contract, forcing you to resign.

The Employment Rights Act 2025 has updated unfair dismissal rules:

• Shorter qualifying period: The service requirement to claim unfair dismissal drops from two years to six months.
• Stronger protection: You gain stronger protection against unfair treatment after only six months of service.

Acas early conciliation and the road to an Employment Tribunal

If internal procedures fail, your next step is usually an Employment Tribunal. However, you must notify Acas for early conciliation before you can file a claim.

• Acas early conciliation: A mandatory process where an impartial officer helps you and your employer reach a legally binding settlement outside of court.
• Time limits: The Employment Rights Bill 2024-25 (not yet enacted as of early 2026) increased the tribunal claim time limit from three months to six months.
• Pausing the deadline: Notifying Acas pauses this countdown clock. Early conciliation can last up to 6 weeks, extendable by agreement, and this time is added to your tribunal deadline.

Case Example:

In Vento v Chief Constable of West Yorkshire Police, the Court of Appeal established guidelines, known as the “Vento bands”, for assessing compensation for injury to feelings in discrimination cases. These guidelines are still used by Employment Tribunals when determining awards for emotional distress caused by unlawful discrimination.

FAQs

How long does a grievance process take? There is no fixed legal timeframe, but Acas requires it to be handled without unreasonable delay. A standard process typically takes 4 to 8 weeks.

Is there a time limit on raising a grievance? No strict internal deadline exists, but waiting can weaken your case. Crucially, the strict six-month Employment Tribunal deadline continues to tick during the internal process.

Can I be dismissed for raising a grievance? No. Dismissal for raising a grievance is automatic unfair dismissal or victimisation. The Employment Rights Bill 2024-25 (not yet enacted as of early 2026) strengthens this protection from an earlier stage.

Following the Acas code ensures your grievance is handled with legal fairness, and the Employment Rights Act 2025 strengthens these protections for shorter-tenure workers. If your internal appeal is rejected, Acas early conciliation is your next step toward a settlement or an Employment Tribunal claim.

This guide provides general information only and does not constitute legal advice.

KEY TAKEAWAYS:

• Acas Code Impact: An employer who unreasonably fails to follow the Acas grievance procedure faces a penalty of up to a 25 per cent increase in tribunal compensation awards.
• New 2026 Protections: The Employment Rights Bill 2024-25 (not yet enacted as of early 2026) has reduced the unfair dismissal qualifying period to six months and extended the tribunal claim time limit to six months.
• The Power of SARs: Raising a Subject Access Request during a grievance may uncover internal communications that are essential for proving discrimination or a breach of contract.