One Incident = One Investigation?

Our Corporate Crime & Investigations Team examines why a single safety incident can give rise to multiple, parallel investigations across different authorities and jurisdictions.

Welcome back to our 2026 monthly series: “Responding to a safety incident – and beyond.”  To help you navigate emerging questions and to guide discussion within your organisation, each month we are providing you with practical advice on responding to a safety incident. This month we consider: does one safety incident mean one investigation?

The short answer is no. A serious health and safety incident can trigger overlapping and parallel investigations.

So, who investigates and for what purpose?

A range of investigations can follow a single safety incident:

• Police (including the British Transport Police) investigate serious criminal offences including homicide-related offences such as Corporate and Gross Negligence Manslaughter.  Where there is a suspicion that a negligent homicide may have caused a work-related death, the police will assume primacy for an investigation but should work with other relevant enforcing authorities under the ‘Work Related Death Protocol’.
• Regulators – a wide range of regulators are responsible for enforcing health and safety legislation. Determining which regulator has jurisdiction to investigate is not always straightforward: make sure that you understand who regulates your business. Key Regulators include:
  • Health and Safety Executive (HSE) – responsible for enforcing health and safety at workplaces including factories, farms, building sites and hospitals.
  • Local authorities – enforce in retail, hotel and catering premises, offices, consumer and leisure industries.
  • Office for Nuclear Regulation – responsible for nuclear installations.
  • Office of Rail and Road – enforce in relation to railways, tram and underground systems.
  • Fire and Rescue Authorities – responsible for enforcing the Regulatory Reform (Fire Safety) Order 2005.

Regulators have a range of enforcement actions available to them, ranging from letters of contravention (notifying a breach of the law), to improvement notices (specifying a timeframe within which the recipient must remedy a contravention) through to a criminal prosecution.

• Independent Accident Investigation Branches – rail, maritime and air accidents may be investigated by the Air, Marine, or Rail Accident Investigation Branches (“AIBs”).  The AIBs do not take enforcement action.  Their sole objective is to determine the circumstances and causes behind an incident, with the aims of improving safety, promoting learning, and avoiding future accidents by making recommendations. However, the report can overlap with other investigations and its conclusions or recommendations may be referenced.
• Coroner – if a fatality has occurred because of a safety incident, a coroner should gather evidence to answer four statutory questions: Who? Where? When? How? A coroner’s inquest is fact-finding only.  If the coroner considers that actions could be taken to prevent future deaths, the coroner must issue a report to the relevant person / organisation – who must respond in writing.
• Internal – an organisation will usually want to run its own investigation to identify what has happened and any remediations or recommendations. This whether the internal report is disclosable in other investigations and so needs careful consideration. We will discuss the practicalities of internal investigations later in our series. 
• Insurers –insurers may need to be notified and so are likely to raise their own enquiries and conduct investigations. 
• Civil claims – civil claims from employees (e.g. personal injury claims by injured parties) or third parties affected by an incident may arise alongside other investigations.  Such claims may also trigger insurance considerations.

Key takeaways

• Multiple agencies may investigate a single incident.  Although there has been one incident, this can trigger multiple investigations – be prepared on how you will manage competing deadlines and information requests.
• Understand who might investigate you for what, and their powers, so that you know what to expect, from whom, can respond appropriately to each agency.  We will discuss the investigatory powers of key enforcement agencies in our next article.
• Take a holistic view.  A range of investigations and related actions may take place concurrently and responses given to one may affect another. You may need to update different stakeholders and review the position across multiple investigations as new evidence comes to light. 

At Burges Salmon, we frequently provide training and advice to corporate clients on managing multi-stakeholder investigations. For more information or to discuss anything in this article, please contact Charlotte Whitaker in Burges Salmon’s Corporate Crime & Investigations team or sign up to our mailing list our Health and Safety mailing list by clicking the link below.

If you want to read the previous article in our series please find this included below: