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Process & Investigation Guidance

Workplace Investigations: Employer Guide

A workplace investigation may be needed after allegations of misconduct, bullying, harassment, discrimination, whistleblowing or serious grievance concerns. The purpose is to establish relevant facts so the employer can decide what, if anything, should happen next. An investigation is not a search for evidence to support a decision already made.

Author: Nectar HR Advisory Team | Legal Context: UK Employment Law, ACAS Code of Practice & Equality Act 2010

At a Glance: Conducting a Compliant Workplace Investigation

  • Define Terms of Reference: Scope the specific allegations, relevant dates, key witnesses, and policies before collecting evidence.
  • Impartiality & Separation of Roles: Keep the investigator separate from the person chairing the subsequent disciplinary hearing wherever practicable.
  • Balanced Fact-Finding: Collate evidence that challenges the allegations just as rigorously as evidence that supports them.
  • No Absolute Anonymity: Avoid promising complete secrecy; natural justice requires the accused to know the case against them.

When does an employer need an investigation?

A workplace investigation may be needed after allegations of misconduct, bullying, harassment, discrimination, whistleblowing or serious grievance concerns. The purpose is to establish relevant facts so the employer can decide what, if anything, should happen next. An investigation is not a search for evidence to support a decision already made.

Start by defining the scope

Write down the allegations, issues to be investigated and the questions the investigation must answer. Identify the relevant timeframe, witnesses, documents and policies. A clear scope helps prevent an investigation from expanding indefinitely while ensuring important issues are not overlooked.

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ACAS Workplace Investigation Protocol: Scoping, Fact-Finding, and Report Delivery

Who should investigate?

Choose someone sufficiently impartial, with the skills and time to investigate properly. Where reasonably practicable, keep the investigator separate from the person deciding any disciplinary outcome. External independence may be especially useful when a senior leader is implicated, accounts conflict or internal relationships have deteriorated.

What evidence should be gathered?

Depending on the issue, evidence might include interviews, emails, messages, rota records, policies, meeting notes or lawfully accessible CCTV. Preserve relevant material promptly. Look for information that challenges as well as supports the allegations. Handle personal data carefully and share it only where necessary.

How should witness meetings work?

Explain the purpose of the meeting and ask open questions before testing specific points. Keep an accurate record and give the witness a fair chance to clarify it. Do not promise complete anonymity: it may be impossible to investigate or conduct a fair later hearing without disclosing relevant details.

What if witness accounts conflict?

Conflicting accounts are common. Consider consistency, contemporaneous records, the opportunity each person had to observe events and any corroboration. Do not assume that the most senior or most confident witness is correct. Where facts cannot reasonably be established, say so.

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What should the investigation report contain?

A useful report explains the remit, steps taken, evidence reviewed and factual findings. It should distinguish evidence from inference and identify unresolved matters. The investigator may recommend whether there is a case to answer, but the disciplinary decision should be made by the appropriate decision maker.

What if the employee is off sick or raises a grievance during an investigation?

Consider adjustments to interviews, timescales and contact. An investigation does not always need to stop, but fairness may require a pause or alternative arrangements. If a grievance concerns the investigator or process, assess that issue independently.

Need an independent workplace investigator?

We provide external, impartial investigation services, interview witnesses, and produce thorough, defensible ACAS reports.

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How Nectar HR can help

Nectar HR undertakes and supports workplace investigations, including complex grievances and misconduct cases. We can help scope allegations, interview witnesses, review evidence and produce clear reports for employers.

Practical Employer Guidance

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