Sussex Police said it was called to a ‘serious collision’ involving a bike and a van in Brighton.
The bike and van were in collision at the junction of Whitehawk Way and Piltdown Road at around 9.36am today (March 24), police said.
The air ambulance attended the scene where paramedics treated the cyclist.
Police said the cyclist, a man in his 50s, had suffered serious head injuries and was taken to Royal Sussex County Hospital.
Anyone who saw what happened is asked to contact police on firstname.lastname@example.org quoting Operation Woodburn.