Workplace Investigation Process Steps

workplace investigation process


Workplace investigations play an important role in resolving disputes at work. If conducted properly, investigations can help to protect the interests of the organisation by identifying wrongdoings and to support the employer with fair, objective and informed decision-making. Handled poorly, however, workplace investigations have the potential to create legal risk and serious reputational harm.

While every investigation will be unique in its facts and circumstances, there are general principles that should be followed to help manage risk and safeguard positive workplace relations.

This workplace investigation guide outlines the process and actions that employers of all sizes should follow when carrying out an investigation into allegations of workplace wrongdoings.


What is a workplace investigation?

Workplace investigations are fact-finding exercises that collect all the pertinent information and evidence relating to an alleged misdemeanour. Making decisions on a workplace disciplinary or grievance without completing a reasonable investigation can render any subsequent decisions or actions taken unfair or unlawful, which can expose the organisation to the risk of legal action.


Following a fair procedure

An employer must ensure they follow a fair procedure for everyone involved in a grievance or disciplinary investigation. As stated above, any decisions made must follow a reasonable investigation, and if it does not, the case is likely to be deemed unfair, risking legal action. While organisations can follow their own workplace investigation process, as a minimum, workplace investigations have to meet the requirements under the ACAS Code of Practice on disciplinary and grievance procedures to be deemed fair and lawful.


Step 1: Pre-investigation

Before initiating an investigation, you should be certain that this is a necessary course of action. Have all informal resolution methods been exhausted? Depending on the circumstances, some issues can be resolved quickly without full intervention.

If it has been decided a full investigation needs to take place, the employer should act promptly as any unnecessary delay may give the perception of unfairness. However, if there is any point along the way where an informal resolution can resolve the matter, it should be always be taken.


What is being investigated?

The employer then needs to determine at the outset of the workplace investigation process what the purpose and scope of the investigation will be, known as ‘terms of reference’, that set out the purpose of the investigation and what the investigator’s role will be and their responsibilities. Terms of reference should include what the investigation will examine, whether a recommendation is needed, how the investigator’s findings will be presented, for example in the form of an investigation report, who the findings will be reported to, and who will be contacted if further advice is needed or any unexpected issues arise. This could be HR or a line manager, for example.


Nominate the investigator

An investigator should be appointed to lead the investigation. While this individual may be someone internal, such as an HR officer, it is crucial that they are not associated or involved with the allegations being investigated, and that they acted both fairly and objectively to establish the facts and allow for a conclusion to be reached based on what is determined to have happened. This can be achieved by collecting evidence supporting the allegation, and evidence refuting it. The investigator’s role is not to prove the guilt of one party, but to see if there is a case to answer.

Organisations are increasingly turning to external investigators to preserve the objectivity of the investigation’s findings, particularly where the case involves complex matters, reputationally sensitive issues, or senior members of the workforce.


How long should an investigation take?

If the employer’s grievance or disciplinary procedures contain suggested or required timescales, these should be followed. If no timescale is specified, the employer should give the employee a provisional timeframe within which the investigation is expected to be completed. That said, the investigator should not be restricted by a provisional timeframe and may find as the investigation progresses, they need to modify it so they can investigate thoroughly. Again, whilst investigations should really be completed as quickly as possible, it also needs to be fair and reasonable if you want to avoid a stint in an employment tribunal. If a new matter comes to light when investigating, the investigator may need to change the terms of reference or authorise a secondary investigation. Although it is preferable to merge the new issue into an existing investigation, this should be avoided if it will become unduly complicated or overly onerous.


Keeping the matter confidential

Investigations should be kept confidential, even if it becomes common knowledge that one is being conducted. You should explain to all staff involved the importance of maintaining confidentiality, and make clear that if any employee breaches confidentiality, it may be viewed as a disciplinary matter. An exception is where the employee who is subject of the investigation is consulting with an employee representative on the matter.


Step 2: Preparing for the investigation

The investigator should begin by drawing up an investigation plan with details such as a witness list, sources of evidence to be collated and examined (work records or emails, for example), investigation timeframe, workplace policies or procedures to be followed, whether recommendations are expected to be given, an outline of the importance of confidentiality, and any other salient points or information necessitating inclusion.


Informing the employee

Unless there is a risk the employee being investigated may tamper with evidence or witnesses, the investigator should inform the employee as soon as they decide to open an investigation. The employer should explain the reasons for the investigation, who will be carrying it out, what they are going to do, that they will talk to any witnesses, and what will happen next. There are ACAS letter templates online that can be used in grievance or disciplinary cases.


Suspending an employee in a disciplinary case

Suspension should only be considered during an investigation if it is needed to protect the investigation, the organisation, other employees, or the employee under investigation. Suspension should not be used as a disciplinary measure while the investigation is ongoing. If suspension is being considered while the investigation underway, the employee should be made aware that this action is not disciplinary action.


Identifying possible sources of evidence

There is no exhaustive list for an investigator to work through to know what sources of evidence they should look at. Every investigation is different and the information and facts that need to be considered will also differ.

Types of physical evidence may include witness statements, emails, paperwork, CCTV footage, receipts, computer data, phone records or attendance records. The investigator must consider how they are going to obtain the information and ensure they follow the law on data protection and other legal obligations.

As the investigation progresses, other sources of evidence may come to light or become relevant. However, the investigator is only tasked with investigating what is reasonably likely to be relevant to the case at hand.


Step 3: Holding an investigation meeting

In both grievance and disciplinary investigations, the investigator may also need to obtain information from the employee, witnesses, and other witnesses which may involve clients or customers during an investigation meeting.


The right to be accompanied

By law, an employee has the right to be accompanied by a ‘companion’ to a meeting or hearing on a grievance issue. However if the issue relates to a disciplinary matter, the employee only has a right to be accompanied to a hearing or meeting where a formal warning is to be given or other disciplinary action is going to be taken. However it is good practice for employers to allow employees to be accompanied in all hearings.

The employee can be accompanied by a colleague, a trained or certified workplace trade union representative, or an employed official of a trade union. Under discrimination law, employers must make reasonable adjustments for disabled employees. This may mean allowing someone else to attend the meeting, for example, a support worker or someone with knowledge of the employee’s disability.


Absence from the investigation meeting

If the employee fails to attend a grievance or disciplinary meeting, it should initially be rearranged. If the employee keeps refusing to attend, the investigator may need to look at all the other evidence and make a reasonable decision from the information they already have in their possession. If the investigation is continued without the employee, the investigator must tell the employee and carry out the investigation in as full and fair a way as possible.


Step 4: Dealing with witnesses

Individuals may need to be interviewed or asked to provide a more formal witness statement. If several people witnessed the same incident, and the accounts are consistent, then the investigator may not need to interview other witnesses unless they require further information or clarification on the matter.

Once the investigator has identified any witnesses, they should ask them to write it down whilst it is fresh in their mind. The investigator can also meet with any witnesses to ask them about the allegation and take notes. At the end of the meeting, the witness should read the notes thoroughly and sign them if they are an accurate reflection of events.


Reluctant witnesses

Some employees may be unwilling or reluctant to provide evidence for an investigation. In such instances, the investigator should explore the reasons behind their reticence and reassure them anything they say will be treated confidentially. Although anonymising witness statements should be avoided where possible. This is because the employee who is under investigation can claim they were disadvantaged because they were unable to effectively challenge the evidence against them. Only if there is a real concern of reprisals should an investigator agree to anonymise a witness statement.


Step 5: Reporting the investigation findings

An investigation report should include all the facts that were and were not established and whether there are any mitigating factors that require consideration. Although an investigator may seek further advice from HR or another third party, the conclusions they reach must be their own.

ACAS has produced an investigation report template that can be adapted for each organisation’s own requirements. But in any event, the report should be written in an objective style, avoid jargon and nicknames, report only facts, include all the evidence that was collected and be concise.

Evidence within the report should be organised into uncontested facts (facts not in dispute), contested facts (those not agreed or contradictory), and unsubstantiated claims (where the investigator cannot prove or evidence an allegation).


Step 6: Concluding the investigation

After the investigator has submitted their report, they will usually not be involved in any further action, other than perhaps discussing the report or attending a hearing to explain their findings.

It is the relevant decision maker rather than the investigator who makes the final decision on what action should be taken on the basis of the investigation, such as whether or not a disciplinary hearing is necessary. If their decision differs from the recommendations in the investigation report, the reasons should be recorded in writing and attached to the report as an addendum.


Retaining investigation reports

There is a general requirement to keep investigation reports for a period of time. It is important to store reports securely and under restricted access; ensure compliance with data protection and other legal requirements. Employees have a right to see any parts of a report that contains information about them, however they should not be able to view information belonging to others.

Should the matter escalate to a tribunal claim, a documented investigation can provide critical support for the employer’s defence.


Need assistance?

Investigation procedures have to be followed fairly and consistently, which can be challenging if the person charged with leading the investigation is not a trained or experienced investigator. DavidsonMorris’ employment law experts are on hand to advise on all aspects of workforce management, including guidance on workplace investigations and disciplinaries. Working closely with our specialist  HR consultants, we provide a comprehensive service for employers ensuring HR and personnel concerns are managed while minimising legal risk. We also act as external investigators, enhancing the credibility of internal HR processes and removing the risk of perceived favouritism or bias in HR investigations. For help and advice, contact us.


Workplace investigation process FAQs

What are the steps in conducting a workplace investigation?

Steps include deciding whether an investigation is necessary, preparing for an investigation, holding an investigation meeting, deal with any witnesses, report the investigation findings, and conclude the investigation.

What happens in an investigation at work?

An investigation happens when someone raises a formal complaint or grievance against another. It gives everyone involved the opportunity to explain themselves, hear the other side and work together with the employer to resolve the situation.

What are employees’ rights during an investigation?

Investigations must be conducted fairly, objectively, without unnecessary delay, and follow a fair procedure. The law gives employees the right to be accompanied to any meeting for grievances and to a meeting or hearing, giving a formal warning or other disciplinary action in disciplinary matters.

Last updated: 8 September 2o23


Founder and Managing Director Anne Morris is a fully qualified solicitor and trusted adviser to large corporates through to SMEs, providing strategic immigration and global mobility advice to support employers with UK operations to meet their workforce needs through corporate immigration.

She is a recognised by Legal 500 and Chambers as a legal expert and delivers Board-level advice on business migration and compliance risk management as well as overseeing the firm’s development of new client propositions and delivery of cost and time efficient processing of applications.

Anne is an active public speaker, immigration commentator, and immigration policy contributor and regularly hosts training sessions for employers and HR professionals

About DavidsonMorris

As employer solutions lawyers, DavidsonMorris offers a complete and cost-effective capability to meet employers’ needs across UK immigration and employment law, HR and global mobility.

Led by Anne Morris, one of the UK’s preeminent immigration lawyers, and with rankings in The Legal 500 and Chambers & Partners, we’re a multi-disciplinary team helping organisations to meet their people objectives, while reducing legal risk and nurturing workforce relations.

Legal Disclaimer

The matters contained in this article are intended to be for general information purposes only. This article does not constitute legal advice, nor is it a complete or authoritative statement of the law, and should not be treated as such. Whilst every effort is made to ensure that the information is correct at the time of writing, no warranty, express or implied, is given as to its accuracy and no liability is accepted for any error or omission. Before acting on any of the information contained herein, expert legal advice should be sought.

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