A 12-year-old girl was seriously injured after being thrown from a car which overturned in a crash.
Police have started an investigation concerning the wearing of seat belts after Friday's accident at Thorrington, near Brightlingsea in Essex.
The injured girl was taken by ambulance to Colchester General Hospital and then transferred to Great Ormond Street Hospital in London.
Her condition was described as "stable" on Sunday afternoon.
A spokesman said on Sunday that police were looking into the circumstances surrounding the cause of the accident.
They were trying to ascertain in particular whether all occupants of the car were wearing seat belts.
The road was closed for over an hour to allow emergency services to carry out their tasks.
The spokesman said: "Inside the car were a 17-year-old male driver, a boy of 13 and a girl of the same age.
"They all lived in Great Bromley and the car had been travelling northwards towards Frating."