The Federation’s Roads Policing Conference was given a lesson in unconscious bias and evidence contamination from a forensic collision investigator.

Frances Senior, an accomplished scene of crime officer with 24 years’ service, addressed delegates in Hinckley, Leicestershire, on Tuesday about the dangers of making assumptions.

She powerfully illustrated her talk with photographs from a real case she had attended in West Yorkshire where a car had collided with a pub wall at speed – launching into the air and leaving four young children critically injured.

Their father, who had been the only one wearing a seatbelt, was at the scene ‘walking wounded’ and the emergency services wrongly assumed he had fallen asleep at the wheel with horrific consequences.

Frances explained that something didn’t add up: “There was a lot of blood on the airbag, a disproportionate amount for the incident. A Burger King bag was upright on the seat and I couldn’t find anyone who would admit to placing it there, and then I found a hammer in the car.

“I started to think that this might be a crime scene. I didn’t raise my concerns early enough because I didn’t want to question the paramedics and traffic experts out of ‘courtesy bias’.

They in-turn had been subject to ‘bandwagon thinking’ and stereotyping. Consequently several hours passed where we had been contaminating the scene with our DNA.”

Ultimately it was revealed that the 29-year-old father, in a moment of psychosis, had attacked the children with the hammer, unclipped their seatbelts and driven into the wall deliberately. They survived but have been left with lifelong injuries.

Frances posed the question: “Are you mindful of your own bias or how your experiences might affect the way you approach a scene?”

Later, delegates heard from Paul Speight of Leicestershire Fire and Rescue Service, on the subject of virtual reality.

A firefighter since 1988, he sought sponsorship in order to develop a stunningly realistic program, which users can enter by wearing a VR headset. They are shown a burned out building and can pick up and examine objects in order to identify the cause of the fire.

Paul suggested that this could become a leading tool for emergency services training in the future: “Learning by doing has a 75 percent retention rate – virtual reality will change the way humans learn.”