What Is Gross Misconduct Under UK Employment Law?

If you’re running a small business, “gross misconduct” is one of those phrases you hope you never need to use - but when something serious happens, you need to act quickly and fairly.

The tricky part is that gross misconduct isn’t just about whether behaviour feels unacceptable. It’s about whether the conduct is serious enough to justify dismissal without notice (often called “summary dismissal”), and whether you’ve followed a lawful, reasonable process.

This guide explains what is considered gross misconduct in the UK, common examples, how it differs from poor performance, and the steps you should take to protect your business while staying on the right side of employment law.

What Does “Gross Misconduct” Mean For UK Employers?

Gross misconduct generally means an employee has done something so serious that it fundamentally damages the employment relationship (in particular, the trust and confidence between you and the employee).

In practical terms, it’s conduct that may justify:

• Summary dismissal (dismissal without notice or pay in lieu of notice); and/or
• Serious disciplinary sanctions (where dismissal isn’t appropriate but a final written warning or other action may be).

There isn’t a single definitive list in legislation that says exactly what is considered gross misconduct in every workplace. That’s because:

• different industries have different risks (e.g. cash handling, care work, safety-critical roles);
• different roles have different levels of responsibility (e.g. manager vs junior staff member); and
• context matters (intent, impact, prior warnings, training, policies, and evidence).

That said, what you can do (and should do) is clearly set expectations in your documents and policies - typically your Employment Contract and staff policies/handbook - so your team understands what behaviours could lead to dismissal.

It’s also worth remembering that even if something is “gross misconduct”, you’ll usually still need to follow a fair investigation and disciplinary process. In practice, many employers use the ACAS Code of Practice on disciplinary and grievance procedures as a benchmark for fairness. Skipping process is one of the fastest ways to turn a justified outcome into an expensive dispute.

What Is Considered Gross Misconduct? Common UK Examples

Employers often ask for a clear list when they search “what is considered gross misconduct”. While there’s no one-size-fits-all answer, there are common categories that regularly appear in workplace policies and in real-life disciplinary cases.

Here are examples that may be considered gross misconduct, depending on the facts and your workplace rules:

1) Theft, Fraud, Or Dishonesty

Dishonesty at work is one of the clearest examples of potential gross misconduct because it goes to trust. This can include:

• stealing cash, stock, equipment, or customer property;
• fraudulent expenses, falsifying receipts, or time sheets;
• deliberately misreporting hours worked;
• unauthorised discounts, refunds, or voids (particularly in retail/hospitality);
• lying during an investigation.

Even if the financial value is small, dishonesty can still be serious - but context matters (training, intent, and whether you’ve communicated rules clearly).

2) Violence, Threats, Bullying, Or Harassment

Physical violence at work is typically treated as gross misconduct. Threats of violence, intimidation, and serious bullying may also fall into this category.

Harassment (including sexual harassment) can also amount to gross misconduct, particularly where it’s repeated or severe, or where it creates a hostile working environment. As an employer, you’ll also want to think about your broader duties under the Equality Act 2010 and health and safety obligations.

3) Serious Insubordination Or Refusal To Follow Reasonable Instructions

Not every disagreement is gross misconduct. But a serious refusal to follow a reasonable and lawful management instruction - especially where it creates safety or legal risks - may justify strong disciplinary action.

Examples might include:

• refusing to follow safety procedures;
• refusing to carry out core duties without good reason;
• encouraging others to ignore lawful instructions;
• serious disrespect or abusive conduct towards managers or colleagues.

This is an area where consistency matters. If you’ve previously tolerated similar behaviour, it may be harder to justify summary dismissal without following a stepped approach.

4) Serious Breach Of Health And Safety

Health and safety breaches can be gross misconduct where they are deliberate, reckless, or put people at significant risk. For example:

• ignoring safety controls or lockout procedures;
• working under the influence in a safety-critical role;
• tampering with safety equipment;
• dangerous driving in a work vehicle (depending on circumstances).

For small businesses, this is a big one - because the consequences can involve not just internal discipline but external scrutiny (accidents, insurance claims, regulator involvement, and reputational damage).

5) Serious Misuse Of Company Property Or IT Systems

Misuse of IT can range from minor policy breaches to serious misconduct. The serious end might include:

• accessing or sharing illegal content using company systems;
• unauthorised access to restricted files (especially personal data or financial records);
• deliberately deleting important business information;
• introducing malware or sabotaging systems.

Monitoring and investigation in this area should be handled carefully due to privacy and data protection rules, so it’s worth ensuring your IT and monitoring policies are clear and up to date.

6) Breach Of Confidentiality Or Data Security

Serious breaches of confidentiality can be gross misconduct, especially where they involve customer information, pricing, trade secrets, or sensitive internal documents.

Examples include:

• sharing confidential information with competitors;
• leaking personal data;
• sending confidential files to a personal email without authorisation;
• posting confidential workplace information online.

If your business relies heavily on confidential know-how, you’ll usually want both contractual and policy protections in place. (And if the situation relates to an accidental disclosure, you’ll often want a careful, evidence-based process rather than an automatic dismissal.)

7) Serious Conflict Of Interest Or Competing Against The Business

Employees working for a competitor, diverting clients, or running a competing business in secret can amount to gross misconduct - particularly where there’s a clear conflict and evidence of dishonesty or harm.

How strong your position is can depend on what’s in the employee’s contract and any relevant policies, plus whether you can show loss of trust, customer impact, or misuse of confidential information.

If you’re unsure how your current documents stack up, it’s often worth checking whether your Employment Contract and policies properly cover conflicts of interest and confidentiality.

For a more detailed checklist-style overview of gross misconduct categories, it can help to compare your own workplace rules against a standard Gross Misconduct Checklist approach.

Gross Misconduct Vs Poor Performance: Why The Difference Matters

One of the most common pitfalls for small businesses is treating performance issues as misconduct (or vice versa).

Here’s the practical difference:

• Poor performance is usually about capability: the employee can’t meet the required standard, even with support, training, or time.
• Misconduct is usually about behaviour: the employee won’t follow rules, behaves inappropriately, or breaches policy/contract.
• Gross misconduct is the most serious form of misconduct: behaviour so severe it may justify dismissal without notice.

If an employee is underperforming, you’ll often need a capability or performance management process rather than jumping straight to dismissal. Many employers use a structured performance plan before termination becomes an option - and done properly, it’s a fair way to give the employee a chance to improve while creating a clear paper trail.

In practice, it can be helpful to run a Performance Improvement Plan where the issue is capability, not conduct.

Getting this classification wrong can increase the risk of claims and disputes, especially if the employee argues they weren’t treated fairly or weren’t told what standard was expected.

How Do You Handle Gross Misconduct Allegations Fairly?

When something serious happens, it’s normal to want to act immediately - especially if your business is small and the impact is huge.

But even if you think the behaviour is clearly gross misconduct, you should still follow a fair process. As a practical benchmark, many employers align their approach with the ACAS Code of Practice on disciplinary and grievance procedures.

That typically means you:

1) Act Quickly, But Don’t Pre-Judge

Start by protecting the business (and people) without assuming the outcome. For example, you might consider a short suspension while you investigate - but make sure any suspension is reasonable, kept under review, and handled carefully to avoid it looking like a punishment before the facts are established. Where suspension is appropriate, it’s commonly done on full pay (unless your contract clearly allows otherwise).

2) Investigate First (Collect Evidence)

A fair outcome starts with a fair investigation. This might include:

• taking witness statements;
• collecting CCTV footage or system logs (where you’re allowed to do so);
• reviewing emails/messages or relevant documents;
• checking policies, training records, and prior warnings.

Ideally, the person investigating should be someone impartial (as far as possible in a small business). If that’s hard due to team size, focus on documenting decisions and avoiding assumptions.

If you want a practical structure for doing this step properly, following a Workplace Investigations process is a sensible starting point.

3) Invite The Employee To A Disciplinary Meeting

Once you have enough information, invite the employee to a disciplinary meeting and clearly set out:

• the allegations;
• the evidence you’re relying on (or at least a summary, depending on circumstances);
• the possible outcomes (including dismissal, if applicable);
• the time/date and who will be present;
• their right to be accompanied at the meeting by a colleague or trade union representative.

Getting the invitation right matters, because it goes to procedural fairness. Using a clear Disciplinary Meeting Invite approach helps keep things consistent and reduces the chance of misunderstandings.

4) Hold The Meeting And Hear Their Side

At the meeting, the goal is not to “win” an argument - it’s to test the evidence, hear explanations, and ensure you’re not missing context.

Keep notes, ask clarifying questions, and avoid making statements that suggest the decision is already made.

5) Decide On The Outcome (And Confirm It In Writing)

If you decide it is gross misconduct and dismissal is appropriate, confirm:

• the decision and the reasons;
• the effective termination date;
• whether notice is paid or not (summary dismissal vs notice);
• any final pay items (holiday pay, etc.);
• the right of appeal and how to appeal.

Be careful with wording. A dismissal letter can end up being key evidence later, so it needs to be accurate, measured, and consistent with your process and findings.

Can You Dismiss For Gross Misconduct Without Notice?

Potentially, yes - summary dismissal is the classic consequence of gross misconduct.

But “can you” and “should you” aren’t always the same thing.

As an employer, you should usually think about:

• Was it actually gross misconduct? (Is it serious enough to destroy trust and confidence?)
• Is there enough evidence? (Would your decision look reasonable if reviewed later?)
• Have you followed a fair process? (Investigation + disciplinary meeting + opportunity to respond, in line with the ACAS Code as a guide.)
• Is dismissal within the range of reasonable responses? (Could a final written warning be more appropriate?)

If you dismiss without notice when the behaviour doesn’t justify it, you can expose your business to claims such as wrongful dismissal (a contractual claim relating to notice pay) and potentially unfair dismissal.

In the UK, most employees need at least two years’ continuous service to bring an ordinary unfair dismissal claim - but there are important exceptions where a dismissal can be automatically unfair (and/or involve discrimination) regardless of length of service, such as dismissals connected to pregnancy/maternity, whistleblowing, asserting statutory rights, health and safety concerns, or trade union activities.

This is why having clear rules in writing is so important. Your staff should know, upfront, what behaviour your business treats as “dismissal-level”. Often, that sits in your policies and handbook - and it’s one reason many businesses put a proper Staff Handbook in place as they grow.

How Do You Reduce Risk When Managing Gross Misconduct In A Small Business?

Small businesses face a particular challenge: you need to move fast, but you often don’t have HR teams, multiple managers, or time to spare.

Here are practical ways to reduce risk without overcomplicating things:

Make Your Policies Clear (Before Anything Goes Wrong)

If your expectations aren’t written down, it’s harder to enforce them consistently. At a minimum, make sure you have:

• a written disciplinary procedure (often aligned to the ACAS Code);
• clear examples of what counts as misconduct vs gross misconduct;
• confidentiality and data handling rules;
• IT/communications rules (including acceptable use);
• health and safety expectations.

These should work alongside your contracts, not contradict them.

Train Your Managers (Even Light Training Helps)

Many disputes aren’t caused by the initial incident - they’re caused by how it’s handled. A short internal checklist for investigations, meeting invites, note-taking, and decision letters can make a big difference.

Be Consistent Across The Team

Inconsistency is a common red flag. If one employee is dismissed for behaviour you’ve overlooked in others, you may find it harder to defend your decision.

That doesn’t mean every situation must be treated identically - context matters - but you should be able to explain why one outcome was more serious than another.

Document Everything

Good records make it easier to show you acted reasonably. Keep:

• investigation notes and evidence;
• meeting notes and outcomes;
• copies of policies and contracts relied upon;
• any prior warnings or training records relevant to the allegation.

Get Advice Early For High-Stakes Situations

If the situation involves senior employees, discrimination risk, whistleblowing, health and safety incidents, or police involvement, it’s usually worth getting legal advice before you finalise the outcome. It can save you a lot of time (and cost) later.

Key Takeaways

• Gross misconduct is usually behaviour so serious it destroys trust and confidence and may justify summary dismissal (dismissal without notice).
• There’s no single legal list of what is considered gross misconduct, so your contracts and policies should set expectations clearly for your workplace.
• Common examples can include theft or dishonesty, violence or serious harassment, serious insubordination, major health and safety breaches, and serious confidentiality or data breaches.
• Poor performance is usually a capability issue and often needs a different process (such as a structured improvement plan) rather than misconduct procedures.
• Even where behaviour looks like gross misconduct, you should usually follow a fair process (often guided by the ACAS Code): investigate, invite the employee to a disciplinary meeting (with the right to be accompanied), hear their response, and confirm the outcome in writing with a right of appeal.
• To reduce risk, small businesses should focus on clear written policies, consistent decisions, and good documentation from day one.

If you’d like help reviewing a gross misconduct situation, updating your workplace policies, or putting the right contracts in place, you can reach us at 08081347754 or team@sprintlaw.co.uk for a free, no-obligations chat.