Detectives are hunting a cycling sex beast who raped a woman at knifepoint in a terrifying attack.

The 33-year-old victim, who is understood to have been working as a vice girl, was assaulted after walking down a passageway with the cyclist in Bradford city centre in the early hours of Monday.

The woman was walking along City Road, at its junction with Menstone Street, in the red light area, when she was approached by the man riding a bicycle.

She walked with him down a nearby passageway, where the man took what is believed to be a knife from his rucksack and threatened her.

He then subjected her to a serious sexual assault.

The woman managed to escape. She was shocked, but uninjured.

Detective Chief Inspector Lisa Griffin, who is leading the investigation, said: “This was clearly a terrifying ordeal for the victim, and specialist officers are working closely with her to establish the identity of her attacker.

“As he was on a bike at the time, people in the area may remember this man and we would like to hear from those people immediately.

“We are treating this as an isolated incident and studying CCTV from the area as part of our inquiries.

“Neighbourhood Policing Team officers are conducting patrols to discuss any concerns locally and also to gather further information.”

The suspect is described as white, about 25 years old, about 5ft 7in and of broad build. He was wearing a woolly hat and a rucksack.

Witnesses, or anyone with information, about the attack at about 4am on Monday should call police on 0845 6060606, or Crimestoppers, in confidence, on 0800 555111.