Internal investigations are familiar but complex. Whether the issue involves employee grievances, misconduct, or regulatory breaches, how an investigation is structured determines its legal defensibility, operational efficiency, and data protection compliance.
The first question when planning the process is deceptively simple: who should conduct the investigation? HR often leads employee-related inquiries, but this may not be appropriate where HR is the subject of the complaint or there’s a risk of bias. Smaller organisations may lack internal capacity and need external support. In sensitive or legally complex cases, appointing lawyers to lead the investigation may be essential to navigate pitfalls and ensure fairness.
If external investigators are engaged, it’s critical to determine whether they will act as data controllers or processors - a distinction with significant implications under the UK GDPR. Roles under data protection law affect contractual obligations, liability, and the level of control your organisation retains over personal data. A bare-bones letter of instruction is unlikely to suffice. Robust data protection clauses are essential.
Next, legal teams must define the scope and purpose of the investigation. These are not just operational questions - they are central to data protection compliance. Under the principle of purpose limitation, personal data must only be processed for clearly defined and lawful purposes. A vague or overly broad scope risks collecting irrelevant data, wasting resources, and inviting legal challenge. Conversely, a scope that is too narrow may miss critical context or fail to address the issue.
The purpose - whether to establish facts, resolve a grievance, or meet regulatory obligations - will shape tone, methodology, and reporting. It also determines whether the organisation has jurisdiction to act. Investigating matters outside your remit can lead to procedural flaws and data protection breaches.
The impact on individuals must also be considered. Where outcomes may affect employment, income, or reputation, a higher standard of care is expected. The greater the stakes, the more rigorous your data protection safeguards must be.
Once the “who,” “what,” and “why” are clarified, attention turns to logistics, methodology, and involvement. Timing is critical, as delays may result in data loss (e.g. expired access logs or overwritten CCTV), while rushed investigations risk overlooking safeguards. Decisions on interview format, for example whether it will be remote or in-person, raise questions about data security. If data crosses borders, additional legal regimes may apply, and documenting data flows becomes essential.
Involving others, such as HR, IT, legal advisors and external investigators, requires careful management of data sharing and role-based access. Internally, clarify who will access investigation data and why. Pre-emptive planning helps defend against challenges to both data processing and the outcome.
Finally, decide who will receive the results. Be clear with participants from the outset about who will receive information. Failures here affect transparency, fairness, and lawful disclosure. If recipients aren’t identified early, you may find you cannot lawfully share the findings - undermining the entire exercise.
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