The point of an investigation is to stop the next one. The HSE’s HSG245, Investigating accidents and incidents, sets out the approach used across UK industry: gather the information, analyse it, identify the risk-control measures that failed or were missing, and produce an action plan. Done properly it separates the immediate cause (the unguarded blade, the missing edge protection) from the underlying causes (the pressure, the training gap, the assessment that was never reviewed) and the root cause in how the work was managed.
Alongside the investigation sit the legal duties. The Reporting of Injuries, Diseases and Dangerous Occurrences Regulations 2013 require the responsible person to report work-related deaths, specified injuries, injuries that keep a worker off normal duties for more than seven days, certain occupational diseases and listed dangerous occurrences to the HSE. Deaths and specified injuries are reported without delay; over-seven-day injuries within fifteen days. Injuries causing more than three days’ incapacity must be recorded even where they are not reportable.
An investigation also has to stand up later. Photographs taken before anything is moved, witness statements taken while memories are fresh, documents secured, and a report that distinguishes fact from inference are what an insurer, a solicitor or an HSE inspector will ask for, sometimes years afterwards.