An armed would-be robber fled empty handed after passers-by intervened to help his victim.
Police are now appealing for anyone who saw the incident yesterday to get in touch before the man strikes again.
A spokesman said: “At about 2.30pm on Thursday, a 25-year-old man was walking along New Hey Road in East Bowling, when he was approached by a man who made demands for his bag.
“There was a struggle and a knife was produced, before a number of other people intervened to help the victim, forcing the attacker to run off empty-handed down Bowling Hall Road.
“It is believed he got into a blue Seat Ibiza, driven by a second man, which then drove off.”
The victim suffered minor facial injuries.
Detective Inspector Neil Benstead of Bradford CID, said: “This was a frightening attack which left the victim quite shaken.
"On this occasion nothing was stolen, but we need to catch this man responsible before he tries something similar."
The suspect is described as white, about six ft tall and of slim to medium build.
He was wearing a black hooded top, black tracksuit bottoms and black trainers. The driver of the vehicle was described as black.
Anyone with information is asked to contact DC Pearman at Bradford CID on 101 or Crimestoppers on 0800 555111.