A woman driver is in a critical condition after allegedly being assaulted following a car crash.

Scotland Yard said the 39-year-old had been “taken unwell” when officers arrived at the scene of a two-car collision at Gants Hill roundabout in Redbridge, east London on Friday evening.

Police said they are investigating a report that the woman, who was driving a Kia Picanto, was assaulted by the male driver of the second car involved in the crash – a Toyota Yaris.

Officers called to the scene just after 6.50pm “immediately” gave the woman first aid ahead of the arrival of London Ambulance Service.

She was taken to an east London hospital where she is in a critical condition.

A 54-year-old man has been arrested on suspicion of assault and is in custody at an east London police station.

Detectives are keen to trace a particular witness – described as a white man and around 6ft 2in – who was at the scene.

They are also appealing for anyone who saw the collision or its aftermath to contact officers on 101, or Crimestoppers on 0800 555 111.