Police are continuing to appeal for witnesses following an accident in the county which left a woman dead and two others fighting for their lives.
The collision took place at 1.20pm on Thursday, on the M1 southbound, about one mile south of Watford Gap services.
It involved a white Mercedes Sprinter van, being driven by a 30-year-old man from Reading, and a silver Mercedes C Class, being driven by a 70-year-old woman from Nottinghamshire.
The Mercedes car was stationary on the hard shoulder when the collision took place.
A 64-year-old woman from Nottinghamshire, who was a passenger in the C Class, died as a result of the collision. The driver and a 70-year-old man from Nottinghamshire who was also a passenger, sustained life threatening injuries.
The driver of the Sprinter van was arrested on suspicion of causing death by dangerous driving and has been released on bail, pending further enquiries.
Anyone with information or who witnessed this incident is asked to call the Drivewatch Hotline on 0800 174615.