Police are appealing for witnesses to a road traffic collision on the A413 near Stoke Mandeville.
A white BMW 5 Series and a purple and black Yamaha motorcycle were involved in the collision on the A413 Wendover Road at the junction with Quilters Way at 5.40pm on Tuesday (15/8).
The motorcycle collided with the side of the BMW as the BMW was making a turn in the road due to stationary traffic.
The motorcyclist, a man in his twenties, was taken to the John Radcliffe Hospital in Oxford with life-threatening injuries, where he remains in a critical condition.
No arrests have been made at this stage of the investigation.
Police operation launched to protect horse riders
Three-storey wedding cake to be removed from Waddesdon Manor
New community listening initiative launched in Bucks
Easy access to drugs and "disappointing" cleanliness levels at Bucks prison
Concerns raised over pedestrian safety in Aylesbury
Movember: Men Walking and Talking Aylesbury's Scott Grover tells us how they're helping local men
