It happened between the B565 between Olney and Lavendon
At around 9.35am on Saturday (18/1) a green Peugeot 206 and a silver Citroen Relay van were involved in a collision.
The driver of the Peugeot, a woman in her fifties, and the driver of the Citroen, a man in his sixties, were taken to hospital with serious injuries where they remain receiving treatment.
Investigating officer, PC Alistair Jarratt, of the Roads Policing Unit based in Milton Keynes, said: “I am appealing for anyone who may have witnessed this collision, or who may have any information about what happened, to please come forward.
“I believe there are motorists who were in the area around the time of this collision and I would urge them to contact us.
“I would also ask motorists to check any dash-cam footage in case it may have captured something that could assist with the investigation.
“Anyone with information can contact police on the non-emergency number 101 or make a report online, quoting reference 43200020409
