Misconduct Investigation Letter UK: Employer Guide
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Part ofUK Employment Law Guide for Employers (2025)
When something goes wrong at work and an employer suspects misconduct, the worst thing to do is jump straight to discipline. A proper investigation has to come first, and that usually starts with a written invitation asking the employee to attend an investigatory meeting.
Getting this letter right matters more than people realise. It sets the tone, records that the employer is following a fair process, and gives the employee a clear idea of what they are walking into. This page walks through what a misconduct investigation letter is for, how it differs from a disciplinary hearing invite, what UK employers should think about before sending one, and where this fits within the wider ACAS framework.
If you are the one doing the investigating, or the one receiving the letter, the points below should help you make sense of the stage you are at.
What this document is
A misconduct investigation letter is the formal note an employer sends to an employee asking them to attend a fact-finding meeting about an allegation or concern. It is not a disciplinary hearing and it is not a decision. It is the step where the employer gathers information, hears the employee's side, and works out whether there is a case worth taking further.
The letter typically explains what the meeting is about in general terms, when and where it will take place, who will be there, and what the possible next steps might be once the investigation ends. In England and Wales, the ACAS Code of Practice on Disciplinary and Grievance Procedures sets the standard most tribunals will measure an employer against.
While the Code itself does not force employers to hold a separate investigatory meeting in every case, a proper investigation is expected, and writing to the employee ahead of it is the clearest way to demonstrate fairness. Clumsy wording at this stage, such as treating it as if guilt has already been decided, can undermine the whole process later.
How to use this document
- Decide whether an investigation is genuinely needed. Not every issue calls for a formal process. Have a quick think about whether the concern is serious enough to warrant investigation, or whether a quiet conversation with the employee would resolve it. Jumping to formality for minor issues can damage trust and create unnecessary friction.
- Appoint someone suitable to run the investigation. Pick a manager or HR contact who has not been directly involved in the events and who can approach the matter with an open mind. The person running the investigation should ideally be different from whoever might later chair a disciplinary hearing, so the two stages stay genuinely separate.
- Draft the invitation letter clearly and neutrally. Explain that this is an investigatory meeting, not a disciplinary hearing, and outline the general nature of the concern. Give the date, time, location, and the name of whoever will attend. Avoid accusatory language, and make clear that no decision has been made about whether misconduct has occurred.
- Think about the right to be accompanied and practical arrangements. The statutory right to be accompanied usually applies to disciplinary and grievance hearings rather than investigatory meetings, but many employers still allow it as good practice. Give reasonable notice so the employee can prepare, and consider adjustments if the person is unwell, neurodivergent, or needs support.
- Keep confidentiality and data handled properly. Only share details with those who genuinely need to know, store notes securely, and handle any personal data in line with UK GDPR and the Data Protection Act 2018. Keep a written record of the meeting and any evidence gathered, since this will matter if the case progresses to a disciplinary stage or ends up at tribunal.
Common questions
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Common questions
Q Is an investigatory meeting the same as a disciplinary hearing?
No, and the distinction matters. An investigatory meeting is a fact-finding exercise where the employer gathers information and hears the employee's version of events. A disciplinary hearing happens later, only if the investigation shows there is a case to answer, and that is where decisions about warnings or dismissal get made. Mixing the two up can make the whole process look unfair.
Q Does the employee have a right to bring someone to an investigatory meeting?
The statutory right to be accompanied under the Employment Relations Act 1999 generally applies to formal disciplinary and grievance hearings, not investigatory meetings. However, many employers allow it anyway as good practice, and some workplace policies give that right explicitly. Check the contract and any internal policy, as ignoring a contractual right can cause problems later.
Q How much notice should an employer give before the meeting?
There is no fixed legal minimum for an investigatory meeting, but the employer should give enough notice for the employee to prepare and arrange support if needed. A couple of working days is usually reasonable, though more complex matters may justify longer. Rushing someone into a meeting the same day tends to look unfair if the case is later examined.
Q Can an employee refuse to attend?
Employees are generally expected to cooperate with a reasonable investigation as part of their duties. Outright refusal without a good reason can itself become a conduct issue. That said, if the employee is unwell, struggling, or has a genuine concern about the process, it is sensible for the employer to listen and, where appropriate, reschedule rather than force the issue.
Q Should the letter spell out every detail of the allegation?
The letter should describe the concern clearly enough that the employee understands what the meeting is about, without being so forensic that it reads like a charge sheet. At the investigation stage, the facts are still being gathered. Being too specific too early can look like the employer has already made up its mind, which is exactly what the process is supposed to avoid.
Q What happens after the investigation ends?
Once the investigator has finished gathering information, they usually produce a report. The employer then decides whether there is enough to justify a formal disciplinary hearing, whether the matter can be dealt with informally, or whether no further action is needed. The employee should be told the outcome, even if that outcome is simply that the matter has been dropped.
Q What if we skip the investigation and go straight to a disciplinary?
That is risky. The ACAS Code expects employers to carry out reasonable investigations before taking disciplinary action, and tribunals can increase compensation by up to 25% where the Code has been unreasonably ignored. Even in apparently clear-cut cases, a short investigation protects the employer and gives the employee a fair chance to respond.
If you're dealing with this kind of situation, speak to an experienced legal adviser who can walk you through it — from £89.
Sources
This guide is based on primary UK law and official guidance.
- Official SourceACAS Code of Practice on Disciplinary and Grievance Proceduresacas.org.uk
- Official SourceACAS guidance on conducting workplace investigationsacas.org.uk
- LegislationEmployment Relations Act 1999 (right to be accompanied)legislation.gov.uk
- Official SourceUK GDPR and Data Protection guidance (ICO)ico.org.uk
Legal helpline
Unsure how to handle a misconduct issue fairly?
Getting the first letter and the investigation stage right often decides how the whole process plays out later. An experienced legal adviser can talk you through the key points based on what you describe, so you feel clearer about the next move before you send anything in writing.
- Plain-English answers to your specific questions about the investigation stage
- Practical perspective on what a fair process looks like in your situation
- What to watch out for when wording the invitation letter based on what you describe
- A clearer sense of how the ACAS Code applies to your circumstances
Legal disclaimer
This article is for general information only. It is a tool to help you find your way — not legal advice, and not a substitute for speaking to a qualified adviser about your situation.