A 15-year-old girl died and her friend suffered critical injuries after the car they were in left the road and smashed into a tree.

The black Toyota Yaris was being driven by a 17-year-old man when the crash happened at about 7.35pm on Saturday (May 21) on the B4030 towards Middle Barton about three-quarters of a mile west of Hopcrofts Holt.

The incident was one of three serious collisions on Oxfordshire's roads in less than an hour on Saturday evening.

The teenager who died was pronounced dead by paramedics at the scene and her friend, also a 15-year-old, was taken to the John Radcliffe Hospital, Oxford, where she remains in a critical condition.

Both girls were rear sear passengers in the car. The driver escaped injury.

The road was closed for four hours to allow police forensic experts to examine the scene.

Just 45 minutes earlier in Oxford, a Volkswagen Golf hit Rose Hill Roundabout on the ring road and turned onto its roof.

Two of the four men inside had to be cut free by firefighters before they could be take to hospital. One of the passengers is described as having serious but not life-threatening injuries. The condition of the other three men is not known.

Police had to close part of the roundabout for about three hours, leading to long tailbacks from Cowley to Heyford Hill.

At exactly the same time a man was driving a car in Baldon Lane in Toot Baldon when he lost control of the vehicle and crashed into a tree outside the Mole Inn pub.

Firefighters had to cut him free and he was taken to the John Radcliffe Hospital.

Pc Robert Mackintosh, of Bicester roads policing department, is investigating the fatal accident at Middle Barton.

He said: "I appeal to anyone who may have witnessed the collision or saw a vehicle matching this description in the locality to contact us."

Anyone with information that could assist police inquiries on any of the three accidents should call 08458 505505 or the anonymous Crimestoppers hotline on 0800 555111.