How to Conduct a Workplace Sexual Harassment Investigation
A trauma-informed guide for UK employers and managers
Sexual harassment in the workplace is not just a policy violation—it’s a breach of trust, safety, and dignity. For those affected, coming forward can be a vulnerable and emotionally complex experience. For organisations, responding with care, fairness, and professionalism is essential—not only to meet legal obligations but to uphold a culture of respect and accountability.
This guide offers a trauma-informed approach to conducting sexual harassment investigations, rooted in UK law and best practice, and informed by ICENA’s survivor-led training and HR Professionals.
What Is a Sexual Harassment Investigation?
A sexual harassment investigation is a structured process to explore concerns of unwanted conduct of a sexual nature. This includes behaviours that may be verbal, physical, visual, or digital, and that violate a person’s dignity or create an intimidating, hostile, degrading, humiliating, or offensive environment.
Examples include:
- Sexual jokes, comments, or innuendo
- Unwanted touching or physical proximity
- Intrusive questions about someone’s body or private life
- Sharing or displaying sexualised images or messages
- “Banter” that crosses boundaries
Importantly, harassment is defined by its impact, not intent. Even if the behaviour was meant as a joke or compliment, it can still be harmful and unlawful.
Investigations are necessary to:
- Centre the safety and wellbeing of those affected
- Prevent further harm or escalation
- Ensure accountability and justice
- Protect organisational integrity and legal compliance
When and Why You Must Investigate
Legal Framework in the UK
Under the Equality Act 2010, employers must prevent and respond to harassment. The Workers Protection Act (2024) introduces a preventative duty, requiring employers to take proactive steps to stop harassment before it occurs.
The ACAS Code of Practice outlines fair procedures for handling grievances and disciplinary matters. While not legally binding, it is considered in tribunal cases and can affect compensation outcomes.
Vicarious Liability
Employers can be held responsible for harassment committed by employees or third parties (e.g. clients, suppliers) if they fail to take reasonable steps to prevent it. This includes harassment by customers, patients, or contractors.
Internal vs. External Investigations
An internal investigation may be appropriate for straightforward cases. However, external investigators recommended when:
- The accused holds significant power or influence
- There are multiple or complex allegations
- Trust or impartiality may be compromised
- The case involves sensitive or high-risk dynamics
External professionals bring neutrality, trauma-informed expertise, and credibility to the process.
Preparing for the Investigation
Immediate Action After a Complaint
When someone discloses sexual harassment:
- Prioritise safety: Consider shift changes, remote work, or paid leave—without penalising the person who disclosed.
- Prevent retaliation: Make it clear that any form of victimisation will not be tolerated.
- Maintain confidentiality: Share information only with those who need to know, and explain this clearly to all parties.
Avoid moving the complainant unless they request it. The person who disclosed should not feel punished or isolated for speaking up.
Appointing the Investigator
Choose someone who is:
- Impartial and not involved in the incident
- Trained in trauma-informed approaches
- Senior enough to manage the process and make decisions
ICENA’s trauma-informed model centres empathy, safety, and survivor autonomy. The investigator should be able to hold space for difficult emotions while maintaining procedural rigour.
Scoping the Investigation
Define the terms of reference:
- What is being investigated?
- Who will be interviewed?
- What evidence will be reviewed?
Set a timeline and communication plan to keep all parties informed and reduce uncertainty. Transparency helps build trust in the process.
Document Collection and Planning
Gather:
- Relevant policies (e.g. dignity at work, code of conduct)
- Prior complaints or disciplinary records
- Emails, messages, CCTV footage, and other digital communications
Be mindful of data protection and privacy laws when handling sensitive information.
Conducting the Investigation
Interviewing the Complainant
Use trauma-informed techniques:
- Create a safe, private space
- Use open-ended questions
- Validate their experience and emotions
- Ask about the impact and their preferred resolution
Avoid judgment, minimisation, or rushing. Survivors may present in many ways, calm, emotional, angry, or withdrawn. All responses are valid.
Let them know they are believed, supported, and that their disclosure will be taken seriously.
Interviewing Witnesses
- Build a timeline of events
- Corroborate accounts
- Assess credibility based on consistency, detail, and demeanour
Offer anonymity where possible and reassure witnesses about confidentiality and support. Be sensitive to the fact that some witnesses may also be affected by the incident.
Interviewing the Accused
- Maintain neutrality and avoid assumptions
- Clarify the nature of the relationship and context
- Allow them to respond fully to the allegations
Ensure they understand their rights and the process. Treat all parties with dignity and fairness.
Handling High-Risk or Complex Cases
Bring in external investigators when:
- The accused holds significant power
- There are multiple complainants
- The case involves criminal allegations
External professionals can ensure objectivity and reduce internal bias. They also bring expertise in managing trauma disclosures and safeguarding concerns.
Evaluating Evidence and Drawing Conclusions
Weigh evidence on the balance of probabilities:
- Is it more likely than not that the incident occurred?
- Consider all accounts, documents, and witness statements
- Distinguish between fact and opinion
Document everything thoroughly to ensure legal defensibility and transparency. Avoid relying on instinct—base conclusions on facts and context.
If accounts conflict, assess credibility based on consistency, plausibility, and corroboration—not on emotional presentation or perceived “normal” reactions.
Final Report and Recommended Actions
The investigation report should:
- Outline the process followed
- Summarise interviews and evidence
- State whether the complaint is substantiated
- Recommend next steps (e.g. disciplinary hearing, mediation, training)
Consequences must align with:
- Organisational policy
- Past precedents
- The severity of the misconduct
Ensure the survivor receives feedback—even if the outcome is not what they hoped for. Transparency and closure are essential.
Post-Investigation: Follow-Up and Prevention
Support for Complainant and Accused
Regardless of the outcome:
- Offer mental health support (e.g. EAP, RCEW or ICENA’s counselling support service)
- Maintain open communication
- Avoid isolating or penalising either party
Support should be ongoing, not just during the investigation. Survivors may need time and space to process the outcome.
Ongoing Monitoring and Culture Change
- Monitor team dynamics and morale
- Address any lingering tensions
- Reinforce respectful behaviour and accountability
Culture change requires visible leadership, consistent messaging, and active listening.
Training and Prevention Strategies
- Regular dignity at work and harassment awareness training
- Promote active bystander interventions (e.g. the 5 Ds: Direct, Distract, Delegate, Delay, Document)
- Encourage open dialogue and feedback
Prevention is a shared responsibility. Everyone plays a role in creating a safe and respectful workplace.
FAQs About Sexual Harassment Investigations
How long should a workplace harassment investigation take?
Investigations should be completed within a reasonable timeframe, typically 4–6 weeks, depending on complexity. Delays must be justified (e.g. illness, annual leave).
Can we investigate if the case is already with police?
Yes. Internal investigations can run parallel to police inquiries. However, avoid prejudicing the criminal case and seek legal advice if needed.
What happens if there is no hard evidence?
Investigators must rely on the balance of probabilities. Credible testimony, consistency, and circumstantial evidence can support findings even without physical proof.
When should you hire an external investigator?
Consider external support when:
- The accused is in a position of power
- There are multiple or complex allegations
- Internal trust or impartiality is compromised
- The case involves sensitive or high-profile individuals
Final Thoughts
Conducting a workplace sexual harassment investigation is a delicate and demanding process. It requires empathy, legal knowledge, and a commitment to fairness. By following a structured, trauma-informed approach, organisations can protect their people, uphold their values, and create a culture of dignity and respect.
