LONDON, July 9 (Reuters) The dramatic moment when a would-be suicide bomber tried to detonate a device on a London underground train on July 21, 2005 was captured by CCTV footage.

The silent footage shows panic and terror in the carriage after Ramzi Mohammed, wearing a distinctive dark New York sweatshirt, stands up at one end of the underground train car with a large pack on his back and tries to detonate a bomb.

Moments before, he is seen turning his rucksack containing the homemade bomb towards one of the passengers, Nadia Baro, and her nine-month-old son.

While the other passengers fled in panic, an off-duty fireman is seen staying behind, gesturing furiously at Mohammed, who appears to be shouting and gesturing back.

''I looked up and saw the man I now know to be Mr Mohammed,'' Angus Campbell told Woolwich Crown Court during the trial.

''He was screaming and shouting and there was smoke issuing from behind his back and down on to the floor.'' Campbell said he was scared but could not leave Baro who was having trouble escaping with her child who was in a buggy.

The footage shows Campbell helping her out and then finds himself in the carriage alone with Mohammed.

''I think I was shouting at him, 'What have you done? What have you done?','' Campbell said.

Mohammed told the fireman: ''What's the matter? It's bread. It wasn't me, it was that'' and looked at the rucksack which he had put on the floor.

Police said Campbell's actions were an ''outstanding example of extreme courage''. One senior officer said he deserved a bravery award for his actions.

As the train pulls into the station, Mohammed flings down the pack and flees with Campbell in pursuit. Footage shows him sprinting through the station, his New York shirt clearly visible.

REUTERS SV PM2036