Beds Police are investigating a collision on the A6 yesterday between a car and a schoolbus carrying children from Barton-le-Clay.
Just after 3.50pm, a black Vauxhall Astra and a white school bus were involved in a collision.
One man in his 60s, the driver of the Astra, suffered serious injuries and has been taken to hospital where he remains in a critical condition. Two passengers in the car sustained minor injuries and have also been taken to hospital.
On the bus were a number of school children, none of whom were seriously injured. All the children were taken away from the scene on a replacement bus.
A spokesman from the Arnold Academy in Barton said: "The accident on the A6 involved a bus with our children on. All our children have avoided serious injury and all got home safely. We will be supporting them in the morning."
The road was closed for several hours following the accident, with traffic diverted down Higham Road.
Sgt Craig Wheeler of the road policing unit said: “We’re asking anyone who saw the collision to come forward, including anyone who has any dash cam footage in the run up to the collision.”
Anyone with any information is asked to call police on 101 quoting Operation Radley.
Alternatively report information at www.bedfordshire.police.uk/report, or call independent charity Crimestoppers on 0800 555 111.