The incident, involving a silver Fiat Punto, a blue Renault Clio and a blue Hyundai IX35, took place shortly after 2.30pm on the B645 Kimbolton Road. A spokesman for Cambridgeshire police said: The driver of the Fiat, a 22-year-old man was air-lifted to Addenbrookes Hospital with life-threatening injuries, where he remains at this time in a critical condition. The drivers passenger, a 19-year-old man, was also taken to Addenbrookes Hospital with serious head injuries and is currently in a critical but stable condition. The drivers of the Renault and Hyundai were both uninjured. Crews from the East of England Ambulance Service and Cambridgeshire Fire and Rescue Service, along with the air ambulance, were all in attendance at the scene. A spokesman for the fire service said: Firefighters used specialist cutting equipment to release two male casualties. A number of other casualties were out of the vehicles on the arrival of the fire service. The road was closed following the incident, but reopened at around 7pm. Anyone who saw the collision or the vehicles immediately beforehand is asked to contact the road policing unit on 101.