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Do I need to carry out an investigation before disciplining an employee?

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If you believe that one of your employees has committed misconduct you may think that swift disciplinary action is the only appropriate response. However, rushing to impose a disciplinary sanction without a reasonable investigation may lead to a costly tribunal claim. Our Employment Law team today discusses whether you must investigate allegations of misconduct and how investigations should be conducted.

Do I need to follow the Acas Code in relation to disciplinaries?

According to the Acas Code of Practice on Disciplinary and Grievance Procedures, “it is important to carry out necessary investigations of potential disciplinary matters without unreasonable delay to establish the facts of the case.” A reasonable investigation is a necessary step in a fair, formal disciplinary procedure. The purpose of an investigation is to:

  • determine if there is a disciplinary case to answer;
  • ensure all parties are treated fairly;
  • gather evidence; and
  • help you decide what to do next.

If the disciplinary issues are not serious and can be addressed by speaking with the employee informally, an investigation may not be necessary.  If after speaking with the employees involved you feel there may be a disciplinary case to answer, you should appoint someone to carry out a formal investigation.

The breadth of your investigation will depend on what the employee is alleged to have done and the complexity of the matter. In some cases it may be necessary to carry out a formal investigatory meeting with the employee, interview witnesses, and review CCTV footage. In cases involving allegations of serious misconduct, suspending an employee may be necessary while evidence is collected, but this will only be justified in limited circumstances and for as short a time as possible.

Risks of not carrying out an investigation into employee misconduct

Failing to carry out a reasonable investigation increases your risk of ending up at the Employment Tribunal, as any subsequent disciplinary action you take is likely to be unfair. If you dismiss an employee with over two years’ service without carrying out an investigation, the employee may claim you acted unreasonably and their dismissal was unfair. If you impose a disciplinary sanction short of dismissal, the employee may allege that by failing to conduct a fair investigation you have breached the implied term of trust and confidence and claim unfair constructive dismissal.

The Employment Tribunal will also take into account the Acas Code when deciding claims and awarding compensation. If the Employment Tribunal finds against you in a claim, it may increase the award you must pay the employee by 25% for unreasonable failure to follow Acas Code.

What if the employee has less than two years’ service?

Employees with less than two years’ continuous service do not have the same protection from unfair dismissal as those with two years’ service and so dismissing them without an investigation carries a lower risk of a tribunal claim. However, there are certain circumstances where all employees, regardless of length of service, may claim automatic unfair dismissal. These include where the employee believes they were dismissed because they:

  • possess a protected characteristic (discrimination);
  • acted as a whistleblower;
  • acted as a trade union representative; and
  • took action at work regarding health and safety.

If you followed a fair procedure that includes a reasonable investigation this may help you demonstrate that any disciplinary action you took was fair, and not done for a reason that could form the basis of an automatic unfair dismissal claim.

Carrying out an investigation with an employee

The investigation should be carried out by someone who is impartial, objective and possesses the necessary training and experience. This could be an HR manager or a senior manager without any prior involvement in the matter. If you are a small business, you may need to consider hiring an external HR consultant to conduct the investigation. Someone other than the investigator should hold the disciplinary hearing if the investigation determines that one is needed.  

The investigator should have a plan outlining:

  • the issues to be investigated;
  • witnesses to be interviewed;
  • additional evidence to be gathered; and
  • any time limits.

The purpose of the investigation is to establish the essential facts, not to prove the guilt or innocence of the employee.

In order to ensure the investigation is as fair as possible, it should be carried out swiftly and without any unnecessary delay. This ensures that evidence and the memories of any witnesses are fresh, and minimises the amount of time the employee has to work with the possibility of disciplinary action hanging over their head.

Carrying out an investigation into misconduct can be a stressful and complicated task for employers, but it is a very important step in a fair disciplinary procedure. If you need help conducting an investigation or disciplinary procedure at your business we can advise you, and can offer HR support. Contact our Employment Law Team today at or call 023 8071 7717.

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This is for information purposes only and is no substitute for, and should not be interpreted as, legal advice.  All content was correct at the time of publishing and we cannot be held responsible for any changes that may invalidate this article.