The Top 4 requirements when considering a workplace investigation in the UK

Share This Post


In the event of a subsequent disciplinary or grievance, as an employer, it is important that you follow a fair process. This means ensuring that a thorough investigation is conducted before taking any action. Following a fair investigation is crucial, as failings in the investigation stage can result in potential unfair dismissal claims brought towards an employment tribunal. Should a case go to an employment tribunal, you will be judged against the ACAS Code of Conduct on disciplinary and grievance procedures, therefore, it is important that you follow this at a minimum.

Appointing an investigator

As per the ACAS Code of Conduct on disciplinary and grievance procedures, to conduct a fair investigation, ‘’where practicable, different people should carry out the investigation and disciplinary hearing‘’. For instance, the formal investigation could be handled by HR, the disciplinary hearing to be conducted by the line manager, and the appeals hearing to be handled by the director. In small organisations it may not be possible to have a different appropriate person appointed for each stage of the disciplinary process. Regardless, the person appointed as the investigator should not be involved in the matter in question, for instance as a witness. To avoid any bias, if practicable, they should not be the employee’s direct line of management, and ideally have received training on how to carry out a disciplinary investigation.


Deciding on the scope of the investigation

The whole point of an investigation is to conduct fair, and unbiased fact finding. It is not to try and find evidence to find one party guilty. A fair investigation should find evidence that both supports the allegation and disapproves it. By establishing the scope and purpose of the investigation, this can be presented to the appointed investigator as a terms of reference to help them when establishing the facts concerning the allegations, and ensure that the investigation remains on track.

When deciding on the scope of the investigation, consider what the investigation is required to examine, how the findings should be presented (e.g. investigation report), and who they should be reported to. This will not only determine the scope of the investigation, but will also help the investigator understand the remits of their role in this investigation, and help ensure all the key facts are responsibly investigated and are relevant to the matter.

Informing the employee of an investigation

The employee needs to be informed that they are facing disciplinary allegations and are being placed under investigation. When telling the employee that they are going to be under investigation, it is recommended that they are notified in advance, and in writing. An explanation should also be provided on why there is an investigation being carried out, who the investigator will be, how long the investigation should take, and what they are going to do.

It is just as important to notify the employee in advance of any investigatory meetings. These notices should include information such as the date, time and place of the meeting. Similarly, the employee should be provided with the reason of the meeting, name of investigator and whether they have the right to be accompanied.

For a letter template, please see ACAS investigation meeting letter templates.

Timing of an investigation

It is imperative that you conduct the investigation as soon as possible, to ensure timely relevance and reliability of sources. This is particularly important when gathering witness statements, as witness statements are more reliable when taken closer to when the events occurred.

While some company policies may have set timescales presented for completing investigations, some investigations may take longer than others. A more serious allegation will have a more in depth and longer investigation, than a less serious allegation. For instance, a simpler case may take a day or two to gather all the readily made information together. However, a serious and more complicated case may take weeks, as this can involve interviewing multiple witnesses, and gathering additional physical evidence such as CCTV recordings.

Therefore, while providing a provisional time-frame is helpful, it is worth noting that you do not have to feel restricted to those time-scales. At the end of the day, you want the investigation to be fair and thorough – so if the investigator feels that they require additional time, then the time-frame shall be amended. However, should there be any delays in the investigation process, then all those involved should be notified, and an explanation should also be written in the investigation report.

Get started

Book a Demo