Grievance

A grievance is a formal complaint raised by an employee with their employer. Raising one before a tribunal claim is not always required — but failing to do so without good reason can cost you up to 25% of your award.

Do I have to raise a grievance before going to an employment tribunal?

You are not legally required to raise a grievance before bringing an employment tribunal claim. However, the ACAS Code of Practice on Disciplinary and Grievance Procedures is a statutory code, and a tribunal must take it into account when relevant. If you fail to follow the Code without good reason, a tribunal can reduce your award by up to 25%. Raising a grievance also creates a paper trail and gives the employer a chance to resolve the matter, which can strengthen your case if it is not resolved.

What should a grievance letter include?

A grievance letter should clearly state: the nature of your complaint; the specific incidents, dates, and people involved; what you want the employer to do to resolve the issue; and any relevant documents or witnesses. Keep the tone factual and professional. Send it to HR or your line manager (unless the complaint concerns them), and keep a copy. If the complaint concerns your line manager, address it to the next level of management or HR directly.

Can I raise a grievance and a disciplinary at the same time?

Yes. If you raise a grievance while a disciplinary process is underway, the employer should normally pause the disciplinary to deal with the grievance first — unless the two are entirely unrelated. The ACAS Code says the grievance and disciplinary processes can run in parallel if the issues are not connected. In practice, tribunals expect employers to deal with a grievance about the conduct of a disciplinary with some care, even if they do not pause it.

What is the 25% ACAS uplift and how does it apply to grievances?

Under Trade Union and Labour Relations (Consolidation) Act 1992 s.207A, if a party unreasonably fails to comply with the ACAS Code of Practice, the tribunal can adjust any award by up to 25% up or down. For grievances, this means: if you raised a grievance and the employer failed to follow the Code (e.g. not holding a meeting, not allowing a companion, not offering an appeal), the tribunal can increase your award by up to 25%. If you failed to raise a grievance when you should have, the tribunal can reduce your award.

When is it too late to raise a grievance?

There is no fixed legal deadline to raise a grievance. However, the closer to your resignation or dismissal, the harder it may be for the employer to investigate properly. For constructive dismissal claims, you should generally raise the grievance before resigning — resigning without raising the issue weakens the claim because it suggests the breach may not have been fundamental. For ongoing issues, raise the grievance as soon as possible after the triggering event.

What happens if my employer ignores my grievance?

If an employer fails to acknowledge, investigate, or respond to a grievance within a reasonable time, that failure itself becomes relevant evidence. It can support a claim of breach of trust and confidence (relevant to a constructive dismissal claim) and will be considered when the tribunal applies the ACAS uplift. Document every step: send a written follow-up, note dates, and keep copies of all correspondence. An ignored grievance is not a dead end — it is a fact the tribunal will weigh.

Why a grievance matters before a tribunal claim

Many employees go straight to the employment tribunal without ever writing down their complaint at work. This is understandable — the workplace relationship has broken down. But the ACAS Code creates a real financial incentive to raise a grievance first.

If you had a genuine opportunity to raise a grievance and did not, a tribunal can reduce your award by up to

. The reduction is not automatic — the tribunal must find the failure was unreasonable — but the risk is real, and in a large award it can be significant.

Conversely, if the employer mishandles the grievance — fails to investigate, refuses to hold a meeting, or denies you the right to bring a companion — the tribunal can

your award by up to 25%.

The grievance procedure under the ACAS Code

• Write it down and send it formally.
• A verbal complaint is not a grievance for Code purposes. Write to your employer — usually HR or your manager — setting out the nature of the complaint clearly. Date it and keep a copy.
• The employer holds a meeting.
• The employer should invite you to a formal grievance meeting to discuss the complaint. You have a right to be accompanied by a colleague or trade union representative. The meeting should be held without unreasonable delay.
• The employer responds in writing.
• After the meeting, the employer should write to you with its decision and the reasons for it. This should happen promptly — the Code suggests without unreasonable delay.
• If you are not satisfied with the outcome, you may appeal, and the employer should hold an appeal meeting. The appeal should ideally be heard by a more senior manager than the original decision-maker.

Grievance and constructive dismissal

claims — where you resign in response to a fundamental breach of contract — the grievance is especially important.

Tribunals expect employees in constructive dismissal cases to have raised the underlying breach with the employer before resigning. Resigning without giving the employer a chance to remedy the situation is often seen as weakening the claim. The question is whether you gave your employer a reasonable opportunity to address the breach before treating the contract as at an end.

If you are in this situation, raise the grievance in writing

resigning or simultaneously. Do not resign and then write the grievance.

Raising a grievance during a disciplinary process

Employees sometimes raise a grievance mid-disciplinary — often about the conduct of the disciplinary itself, or about a separate matter that has just come to light. The ACAS Code says that where a grievance is raised during a disciplinary, the employer should consider whether the disciplinary should be paused to deal with the grievance first.

If the grievance and the disciplinary concern entirely separate matters, they may run in parallel. But where they overlap — for example, where the grievance is that the investigation was conducted unfairly — the employer should deal with the grievance before concluding the disciplinary.

Constructive dismissal

ACAS early conciliation

ACAS Code of Practice 1: Disciplinary and Grievance Procedures

Grievance procedure step by step

Grievance — what it is and how to raise one

A grievance is a formal complaint to your employer. This guide explains the ACAS Code of Practice on grievances, the 25% uplift.

Start My Claim — UK Legal Case Builder

Build and run your own employment tribunal, small claims, scam refund or renters' rights case with Start My Claim.