A woman suffered serious head injuries after a car cut in front of her bike, causing her to fall off.
Police are now hunting the driver of the car, who did not stop at the scene of the incident, on Breck Road, in Poulton.
This incident has left a cyclist with a serious injury and I am keen to speak to anyone who saw what happened to come forwardSgt Rob Gomery
The cyclist, 62, was travelling along the road, close to the junction with Moorland Road, when she was overtaken by a light blue hatchback, police say.
The car then turned in front of her, causing the accident.
The woman was taken to Royal Preston Hospital, where she was in a serious condition on Wednesday night.
Police are also appealing for the driver of another car, which overtook the cyclist moments before the collision, at around noon on Wednesday, to come forward and speak to them.
Sgt Rob Gomery, of the Road Policing Unit, said: “This incident has left a cyclist with a serious injury and I am keen to speak to anyone who saw what happened to come forward.
“I would also appeal to the driver of the car involved to get I touch with us so that we can establish exactly what has happened.”
Anyone with information should contact 101.