Police today released further information about a fatal crash on the M40 as they renewed an appeal for witnesses.

At 5.30pm on Saturday, July 12, a blue Ford Fiesta and white, long wheel base, high top Ford Transit van, registration KN03 YRR, collided between junctions seven to six, between Milton Common and Lewknor. Both vehicles left the carriageway went down the embankment and into a field.

The Fiesta overturned, trapping the three people inside. Ross Shears, a 29-year-old man from Crowborough, East Sussex, was a passenger in the Ford Fiesta and was pronounced dead at hospital.

The van drove from the scene across the field before coming to rest in a ditch. The occupants left the scene and ran off.

Sgt Jack Hawkins added: “We are trying to trace three possible witnesses who attended the collision scene and could help us with our enquiries.

“The first is a man who gave first aid to the occupants of the fiesta. He is white, about 40 years old, medium to stocky build, 5ft 6ins to 5ft 8ins, tanned with short, spiky dark hair."He was wearing glasses and had a foreign accent that has been described as South African. He was wearing a black, short sleeved rugby-style top with the words New Zealand printed on the front. The shirt also had a white collar and grey flecked panels running down each side.

“There were also a man and woman who comforted a relative of Ross Shears at the scene. The woman is possibly called Leila and we believe that she could work in a hair salon in London.

“We want to trace these people and I urge anyone who recognises these descriptions to contact me.”

Anyone who witnessed the collision or has any information can contact Sgt Jack Hawkins via the Thames Valley Police 24-hour non-emergency number, 0845 8 505 505.

If you do not want to talk to the police, call the Crimestoppers charity anonymously on 0800 555 111.