A man sustained a serious head injury during a collision on the A43 near to the Hardwick turn, early on Sunday morning.
The 30-year-old was driving a silver Renault Scenic on the northbound carriageway when it was in collision with a black Ford Galaxy travelling in the opposite direction.
The Renault driver was taken to University Hospital Coventry with a serious head injury while the 71-year-old man driving the Ford was taken to Northampton General Hospital with minor injuries.
Police would like to speak to anyone who may have witnessed this incident or who may have any information regarding it.
Anyone with information can call the Drivewatch Hotline on 0800 174615.