A 22-year-old man was seriously injured in a road traffic collision, near the Northamptonshire border.
The single-vehicle accident took place at about 5am on Sunday on the A361 Banbury Road, Chipping Warden, when a black Seat Ibiza FR, left the road and hit a tree.
The driver was taken to John Radcliffe Hospital in Oxford with multiple broken bones.
Police would like to speak to anyone who may have witnessed the accident or who may have witnessed a black Seat Ibiza travelling on the A361 in the early hours of Sunday morning.
Witnesses or anyone with information is asked to contact police on 0800 174615.