Detectives are appealing for witnesses following a crash between Ashby and Coalville on Monday 6th July.
Police say it happened on the A511 at Sinope shortly after 8.30pm and involved a white Vauxhall Vivaro van and a white Mercedes CLA.
The van was travelling from Ashby towards Coalville and the Mercedes was travelling in the opposite direction.
The driver of the Mercedes, a 20-year-old man, was taken to the Queen’s Medical Centre in Nottingham where he remains in a life-threatening condition.
The driver of the van, a 32-year-old man, was also taken to the Queen’s Medical Centre where he remains in a serious but stable condition.
The road was closed while emergency services attended the scene and reopened shortly before 2am.
Detective Sergeant Gary Haines, from the force’s Serious Collision Investigation Unit is asking for anyone with information to get in touch.
He said: “I’m particularly keen to speak to anyone who was travelling on the A511 – in either direction – around the time of the collision who has a dashcam installed in their vehicle.
“I’d also like to speak to anyone who saw the collision occur.
“Likewise, did you see either the white van or white Mercedes beforehand? If so, then please contact police. Any information you have could help with our investigation.”