A moped rider was punched in a road rage incident on the A43 at Walgrave.
The 16-year-old-victim was riding his blue Kinroad XT moped in Walgrave between 1.20pm and 1.45pm on Christmas Eve when a driver swore at him and then pulled in front of him and braked.
This caused the moped to collide with the car, at which point the driver got out of the car and punched the victim in the nose.
The driver was described as white and aged in his late 20s with medium blonde hair and was wearing a grey T-shirt and jeans.
He was driving a white VW Golf with tinted windows and a damage mark on the rear of the vehicle.
Anyone with information should contact Northamptonshire Police on 101 or call Crimestoppers, in confidence, on 0800 555111.