How to Handle a Grievance at Work: A Guide for Employers
Nobody enjoys a grievance. Not the person raising it, not the person it's raised against, and certainly not the manager or business owner who has to deal with it. But grievances are one of the most common — and most commonly mishandled — people issues in UK workplaces. And getting it wrong doesn't just damage relationships. It creates legal exposure that can follow a business for years.
I've investigated and advised on hundreds of grievances across regulated industries, manufacturing, charities, and professional services. The patterns are remarkably consistent. Here's what employers actually need to know.
What a grievance is (and what it isn't)
A grievance is a formal complaint by an employee about their employment. That might relate to their treatment by a manager or colleague, a decision that's been made about their role or conditions, a perception of unfairness, or a concern about behaviour they've experienced or witnessed.
It's not the same as a casual moan. Employees complain about things all the time — that's normal. A grievance becomes a grievance when it's raised formally, usually in writing, under your grievance procedure. Some employees will explicitly say "I want to raise a grievance." Others will send an email that reads more like a frustrated rant but contains enough substance to trigger your process. Learning to recognise the second type is important, because ignoring it is one of the most common mistakes employers make.
It's also not a performance issue in disguise. Sometimes managers treat a grievance as evidence that the employee is "difficult" rather than engaging with the substance of what's been raised. That instinct is understandable. It's also dangerous.
The ACAS Code of Practice
This is the bit you cannot afford to get wrong.
The ACAS Code of Practice on Disciplinary and Grievance Procedures isn't legislation, but employment tribunals are required to take it into account when considering relevant cases. If you've unreasonably failed to follow it, any tribunal award can be increased by up to 25%. That uplift alone can turn a manageable outcome into a painful one.
The Code requires, at minimum, that the employer lets the employee set out their grievance in writing, holds a meeting to discuss it, allows the employee to be accompanied, makes a decision, and offers a right of appeal. That sounds simple. In practice, each of those steps has pitfalls that trip employers up repeatedly.
Where employers go wrong
I could write a book on this, but the same mistakes come up again and again.
Not taking it seriously enough. A manager receives a grievance and treats it as an inconvenience rather than a process that needs following. They have an informal chat, think it's resolved, and move on. Then the employee resigns six months later and claims constructive dismissal, citing the unresolved grievance as evidence that the employer didn't care. This happens more often than you'd think.
Investigating their own grievance. The grievance is about a senior manager. That same senior manager — or their close colleague — is appointed to investigate. The outcome is predictable, and so is the tribunal's view of it. The person investigating a grievance should be independent of the complaint. In smaller businesses this can be genuinely difficult, which is where external support earns its value.
Confusing investigation with outcome. The investigation meeting is for gathering information. It's not for reaching conclusions, making judgements, or telling the employee why they're wrong. I've seen investigation meetings where the manager spends the entire time defending the person being complained about. That's not an investigation. It's a rebuttal. And it looks terrible if it ends up in front of a tribunal.
Dragging it out. Grievances should be dealt with promptly. The ACAS Code doesn't specify exact timescales, but "promptly" means weeks, not months. Every week a grievance sits unresolved, the relationship deteriorates further, the employee's trust erodes, and the risk of a constructive dismissal claim increases. I've seen grievances take six months to conclude. By that point, the working relationship is usually beyond repair regardless of the outcome.
Failing to keep records. If it wasn't documented, it didn't happen. That's an exaggeration, but only just. Investigation notes, meeting minutes, the decision rationale, the appeal outcome — all of it needs recording. Not because you're building a legal file, but because if a tribunal asks to see your process eighteen months later, you need to be able to show it.
The investigation itself
This is the part most employers find hardest, and it's where the quality of your process makes or breaks the outcome.
A grievance investigation should be thorough, impartial, and proportionate. That means interviewing the person who raised the grievance, interviewing the person it's been raised against, interviewing any relevant witnesses, and reviewing any documentary evidence — emails, messages, records, policies.
The investigator's job is to establish the facts as far as reasonably possible. Not to take sides. Not to prove or disprove the grievance. Just to find out what happened. The analysis and conclusions come afterwards, informed by the evidence rather than by assumptions or office politics.
In practice, this requires a skill set that most line managers simply don't have. Knowing how to ask open questions, how to test credibility without being adversarial, how to weigh conflicting accounts, how to distinguish between a genuine complaint and an interpersonal conflict that both parties have contributed to — these are specialist skills. Expecting a manager whose day job is running operations to suddenly become an impartial investigator is one of the biggest process risks in people management.
The outcome meeting
Once the investigation is complete, the employee should be invited to a meeting where the findings and decision are communicated. The decision should be explained clearly, with reference to the evidence gathered. If the grievance is upheld, the employer should explain what action will be taken. If it's not upheld, the employer should explain why, with enough detail for the employee to understand how the conclusion was reached.
This is not the place for vague reassurances or corporate platitudes. "We take all concerns seriously" means nothing if you can't explain specifically what you found and why you reached the decision you did.
And always — always — offer a right of appeal.
When grievances signal something bigger
Here's the thing that gets missed. A grievance is a data point. One grievance might be an isolated issue. Two grievances about the same manager, or the same team, or the same type of behaviour, is a pattern. And patterns tell you something about your culture, your management capability, or your working environment that a single investigation will never fix.
The businesses that handle grievances well don't just process them and move on. They ask what caused them. They look at whether their management development is adequate, whether their policies are clear, whether their culture allows problems to be raised informally before they escalate. They treat grievances as intelligence, not just administration.
Practical steps for getting it right
Make sure your grievance procedure is written down, accessible, and current. Not a document from 2017 buried in a shared drive nobody uses.
Train your managers. Not a half-day course they forget by Friday — ongoing development in how to manage people through difficult situations. The return on this investment is enormous.
When a grievance lands, take it seriously from day one. Acknowledge it promptly, appoint an appropriate investigator, and set a realistic timeline. Communicate that timeline to the employee and stick to it.
If the grievance is complex or sensitive — particularly if it involves senior people, discrimination allegations, or whistleblowing — consider bringing in external support for the investigation. The cost of an independent investigator is a fraction of the cost of a tribunal claim arising from a flawed internal process.
Document everything. Not obsessively, but thoroughly enough that you could explain your process and reasoning to a stranger twelve months later and it would make sense.
And follow up. After the grievance is concluded, check in with the employee. Not once — over the following weeks and months. Make sure the resolution is holding and the working relationship is sustainable. This is where most employers stop paying attention, and it's often where things quietly fall apart.
The bottom line
Grievances aren't pleasant, but they're not the enemy. A well-handled grievance can actually strengthen trust — it shows employees that raising concerns leads to a fair process and a considered outcome, rather than being ignored or punished for speaking up.
A badly handled grievance does the opposite. It tells your workforce that the process is performative, that outcomes are predetermined, and that raising concerns is career-limiting. That message travels fast, and it's very hard to undo.
If you're a business owner or MD reading this and recognising some of the mistakes I've described, you're not alone. Most businesses get grievance handling wrong at some point. The question is whether you fix the process before it costs you — in money, in talent, or in reputation.
Need support?
I advise businesses across the UK on grievance management, investigations, and wider people leadership. If you've got a live grievance and you're not confident in your process, or if you want to make sure your approach is robust before something lands, I offer a free discovery call.