What is gross misconduct?
Gross misconduct is behaviour so serious that it fundamentally destroys the trust and confidence at the heart of the employment relationship. Unlike ordinary misconduct, which is dealt with through warnings and progressive discipline, gross misconduct can justify summary dismissal. That means terminating the employee's contract immediately, without notice or pay in lieu of notice.
The key word here is "can." Gross misconduct does not automatically mean you must dismiss. It means you are entitled to consider dismissal as a reasonable response. But you still need to investigate, hold a hearing, and make a fair decision before you act. Skipping that process is one of the most common and costly mistakes employers make.
Common examples of gross misconduct
While every case turns on its own facts, the following are widely recognised as potential gross misconduct:
- Theft or fraud. Taking company property, falsifying expense claims, or misusing company funds.
- Violence or threats of violence. Physical aggression towards colleagues, clients, or visitors.
- Serious health and safety breaches. Deliberately ignoring safety procedures in a way that puts people at risk.
- Gross insubordination. A deliberate and serious refusal to follow a reasonable management instruction.
- Bringing the company into serious disrepute. Conduct outside work that damages the employer's reputation, where there is a clear link to the employment.
- Deliberate damage to property. Intentionally destroying or damaging company equipment, stock, or premises.
- Serious breach of confidentiality. Sharing sensitive business information, client data, or trade secrets without authorisation.
- Being under the influence of drugs or alcohol at work. Where this creates a risk to safety or performance and is prohibited by company policy.
- Serious bullying or harassment. Conduct that is severe enough to constitute a single act of harassment under the Equality Act 2010, or a sustained pattern of bullying.
- Serious negligence causing substantial loss. Carelessness so significant it causes major financial or operational damage to the business.
This is not an exhaustive list, and your employee handbook should set out the types of behaviour your organisation treats as gross misconduct. If your handbook does not include a clear list, you are already on the back foot if a dismissal is challenged at tribunal.
What is NOT automatically gross misconduct
Employers sometimes overreact to situations that, while frustrating, do not meet the threshold for gross misconduct. These include:
- Occasional lateness or unauthorised absence
- Minor breaches of policy, such as personal phone use during work hours
- Personality clashes between colleagues
- A single instance of poor performance or a mistake
These issues fall under ordinary misconduct or capability, and should be addressed through informal conversations, policies and procedures, or a progressive disciplinary process. Jumping straight to dismissal for ordinary misconduct is a fast track to an unfair dismissal claim.
The investigation process
Even when the misconduct seems obvious, you must investigate before making any decision. This is not optional. Tribunals consistently find dismissals unfair where the employer failed to carry out a reasonable investigation.
Suspend on full pay. If the allegation is serious enough that the employee cannot remain in the workplace while the investigation takes place, you may suspend them. Suspension must be on full pay, for the shortest time necessary, and you must make clear it is a neutral act, not a punishment. Review the suspension regularly.
Gather evidence. Collect relevant documents, CCTV footage, emails, or system logs. Interview witnesses separately and record their accounts. Keep everything in writing.
Interview the employee. Give them an opportunity to explain their version of events during the investigation stage. Their account may reveal mitigating circumstances or cast doubt on the initial allegation.
Keep written records. Document every step. If the case goes to tribunal, the quality of your records will be scrutinised closely.
The disciplinary hearing
Once the investigation is complete, if there is a case to answer, you must invite the employee to a formal disciplinary hearing.
The invitation must be in writing and provide at least 48 hours' notice. It should clearly state the allegations, include copies of the evidence you will rely on, and remind the employee of their right to be accompanied by a colleague or trade union representative.
At the hearing itself, present the evidence and give the employee a full opportunity to respond. Listen to their explanation. Ask questions to clarify. Do not go into the meeting having already made your decision. Tribunals can tell when a hearing was a rubber-stamping exercise, and they do not look kindly on it.
Making the decision
After the hearing, take time to consider the evidence on the balance of probabilities. You do not need to prove the misconduct beyond reasonable doubt. You need to show that you had a genuine belief in the employee's guilt, that belief was based on reasonable grounds, and you carried out a reasonable investigation. This is known as the Burchell test, from the 1978 case of British Home Stores v Burchell.
Consider mitigating factors before reaching your decision. Length of service, a previously clean disciplinary record, provocation, and personal circumstances can all be relevant. Ask yourself: is summary dismissal proportionate to the misconduct? Would a reasonable employer dismiss in these circumstances?
If the answer is yes, you may proceed with summary dismissal. If there are strong mitigating factors, a final written warning may be more appropriate even for gross misconduct. In some cases, a settlement agreement may offer a cleaner resolution for both parties, particularly where the relationship has broken down irretrievably.
Summary dismissal: getting it right
Summary dismissal means the employment ends immediately, with no notice period served. However, you must still:
- Pay any accrued but untaken holiday
- Provide written confirmation of the dismissal, including the reasons
- Offer the right to appeal the decision
- Process the final payslip and P45 promptly
Withholding holiday pay as a form of punishment is unlawful. The employee is entitled to payment for any holiday they have accrued but not taken, regardless of the reason for dismissal.
Common mistakes that lead to tribunal claims
Having supported hundreds of businesses through disciplinary processes, we see the same mistakes repeatedly:
Acting in the heat of the moment. A manager witnesses misconduct and dismisses the employee on the spot. No investigation, no hearing, no right of reply. This is almost always unfair, however serious the misconduct.
Not suspending on full pay. Suspending without pay before a decision has been made is a breach of contract and will undermine your position at tribunal.
Not allowing the employee to respond. The hearing must be a genuine opportunity for the employee to put forward their case. If they were not given that chance, the dismissal is procedurally unfair.
Not offering an appeal. The Acas Code of Practice requires you to offer an appeal. Failure to do so can result in a 25% uplift on any tribunal compensation.
Inconsistency. If you dismissed one employee for misconduct but gave another employee a warning for the same behaviour, you will struggle to defend your decision. Consistency matters.
Not defining gross misconduct. If your contracts of employment and employee handbook do not list examples of gross misconduct, the employee can argue they did not know their behaviour could result in summary dismissal.
Why getting this right matters more than ever
From January 2027, the qualifying period for unfair dismissal claims drops from two years to six months under the Employment Rights Act 2025. The compensation cap for unfair dismissal is also being removed. This means more employees will have the right to challenge their dismissal, and the financial consequences of getting it wrong will be significantly higher.
If you are unsure whether a situation constitutes gross misconduct, or you need support running a fair disciplinary process, get professional advice before you act. The cost of a phone call to an HR consultant is a fraction of what a tribunal claim will cost you.
How Rebox HR can help
We support businesses across the UK with disciplinary and grievance processes, from conducting investigations to chairing hearings and advising on outcomes. For a broader look at the full fair dismissal process, including capability and redundancy, see our detailed guide. If you are facing a potential dismissal situation and want to make sure you handle it correctly, get in touch for a free consultation. We will help you protect your business while treating your people fairly.
