Thames Valley Police is appealing for witnesses to a serious collision on the M4 in Berkshire.
The incident took place around 3.15am on Saturday, May 5.
A white VolksWagen Crafter van and an articulated lorry were involved in the collision on the westbound carriageway between junction 8/9 (Maidenhead) and junction 10 (Reading/Wokingham).
The male passenger of the van was taken to the John Radcliffe Hospital with serious injuries and remains in hospital in a serious but stable condition.
The driver of the van, a man was taken to the Royal Berkshire Hospital with minor injuries and was sent home on the same day.
The lorry driver was uninjured.
Investigating officer PC Marcus Audoin, of the Joint Operations Unit for Roads Policing, said:
“This was a very serious collision and it is important that we speak to anyone who witnessed what happened.
“If you saw this incident take place, or saw the vehicles before the collision, please come forward and speak to police.”
Anyone with information about the collision is asked to call the 24-hour Thames Valley Police enquiry centre on 101 quoting the reference 43180135190.