A man has died in hospital following a collision on the A14 at Leighton Bromswold last month.
At about 7pm on Sunday, June 24, a white Toyota Auris and a silver Mini Cooper collided on the eastbound carriageway.
The driver of the Toyota, 80-year-old John Swannick, of Woodside Drive in Redbrook, Shrewsbury, was airlifted to Addenbrooke's Hospital, in Cambridge, where he died of his injuries on Friday.
His passenger, a woman in her 70s, was also taken to Addenbrooke's Hospital with serious but not life-threatening injuries and has since been released.
The driver of the Mini, a woman in her 50s, from Kent, suffered serious injuries and was also taken to Addenbrooke's Hospital. She has since been released and is recovering at home.
Officers would like to hear from anyone who witnessed the collision, or either of the vehicles in the lead up to it.
Anyone with information is asked to contact the road policing unit at www.cambs.police.uk/report and quote incident 394 of 24 June, or call 101.