Overnight frost is thought to have been a factor in the early-hours crash near Swaffham that claimed the life of a 17-year-old girl.

Officers from Norfolk Constabulary spent the day investigating the single-vehicle accident, which happened on the North Pickenham Road at Sporle at 12.30am today and involved a black Seat Arosa car.

The force said the vehicle contained three people when it left the road and collided with a tree.

The girl was a back-seat passenger and suffered fatal injuries. The driver was unhurt, and another passenger suffered minor injuries, said police.

The victim's name was being withheld until next of kin had been told.

This evening, a police spokesman said the cause of the crash had yet to be confirmed, although the overnight road conditions were thought to have contributed to the tragedy.

Roads across mid- and west Norfolk were treacherous early this morning after the rainfall of hours earlier turned to ice as temperatures plummeted below zero.

Anyone with information about the crash is being asked to call Norfolk police on 101 and speak to the Serious Collision Investigation Team based at Wymondham.