CCTV has failed to capture the moment a female commuter was pushed on to a live railway line on Wednesday, police have admitted, and the footage did not identify the men who shoved her after she told them to stop smoking.

Linda Buchanan suffered a broken wrist and heavy bruising after the attack at Farningham Road station in Kent during the morning rush hour, witnessed by dozens of commuters.

But British Transport Police said today that footage provided to them from the station's four cameras did not show the full incident and has not given them a clear image of the perpetrators.

Officers are now looking at CCTV from more than a dozen other stations along the line between Farningham Road, near Swanley, and London Victoria, in the hope of turning up usable pictures.

A British Transport Police spokeswoman said: “We are continuing our investigation with an appeal to the people involved to hand themselves in. We are looking at CCTV from other stations in previous days.”

She told Times Online: "We've found pieces of the incident, but haven't captured the whole incident. We have some blurry images of the two offenders." These were not of sufficent quality to identify the men, she said.

A spokeswoman for Southeastern rail said of the footage: "We're disappointed that it hasn't helped the police as we hoped it could."

No arrests have yet been made. One of the wanted men has been described as white, in his mid-twenties, and about 6ft with a stocky build and short cropped brown hair. He was wearing beige shorts, a green round-necked T-shirt and trainers. The second was described as white, of medium build, in his early twenties, and wearing bright red shorts and a dark top.

The attack was witnessed by numerous commuters on a platform that was described as "packed". It came after Mrs Buchanan had told the men on Monday and Tuesday mornings to stop smoking, which has been banned on railway platforms since last year.

The men made obscene gestures at her as she walked past them soon after 7am on Wednesday, according to the police. When Mrs Buchanan told them to "grow up", the men pushed her and she stumbled backwards on to the track.

One source suggested they had not meant to throw her on to the tracks. Another witness said: "A scuffle broke out and she was shoved on to the tracks, then a Metropolitan Police officer who was off duty but on his way to work chased the two but they ran off the platform via an exit and managed to escape."

Detective Inspector Bob Richardson, of British Transport Police, said after the incident: “The woman was very lucky she was not more seriously injured. The third rail carries 750 volts of electricity and she could have been electrocuted or even struck by an early morning train.”

Speaking later from her home, Mrs Buchanan herself said: "I feel I'm just lucky to be alive. It could have been a lot worse than it is and I'm just shocked by the whole experience."

A spokesman for Southeastern Trains said on Wednesday: "We are appalled by this incident and hope that the perpetrators are quickly identified."

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