At around 20:20 on Saturday (5th October), a black Volkswagen Polo and a Tesco delivery van collided on Afton Road on the bend which sits between Military Road and Manor Road.
The Volkswagen had been travelling northbound, and the van was travelling in the opposite direction.
The 17-year-old Volkswagen driver sustained serious and life-changing injuries in the crash, including 2 broken legs, and was flown to Southampton General Hospital. His passenger, a 17-year-old girl, sustained serious injuries. The van driver was uninjured.
Hampshire Constabulary are asking anyone with dashcam footage of this incident, or who witnessed it and has any information, to get in touch.
Anyone with information is asked to contact Police on 101, quoting 44190356464.