Lots of clues in latest bombing....

This time around, the bombers left a lot of clues...

he bomber at Shepherds Bush was startled when the blast from his device merely blew him on to his back, rather than kill him outright. Passengers who saw the explosion said that he appeared shocked that he was able to walk away.

Police sources said that all four detonators were homemade. They said that the detonator used in the attack at Warren Street station consisted of nails packed around explosive.

Sir Ian Blair, the Metropolitan Police Commissioner, said that the intention of the terrorists must have been to kill, but he added that it was too early to conclude whether the latest attacks were the work of the same network that caused such carnage a fortnight ago.

He added: “There is a resonance here. There were four attacks and there were four attacks before. We do believe that this may represent a significant breakthrough in the sense that there is forensic material at these scenes.”

Counter-terrorist experts believe that the failure of the devices will provide fingerprints, DNA and possible matches to the bombs used on July 7. Closed-circuit television from Underground stations and the streets, witness statements and descriptions provided by passengers will be a major part of identifying and catching the bombers.

Senior police officers accepted that they could have been facing fresh casualties across London. Sir Ian said that detectives had begun assembling details of the would-be bombers and he urged the public to send digital photographs or mobile phone images to a Scotland Yard website.

Police praised three men, believed to be two officers and a member of the public, who tackled the bomber at the Oval, ripping his rucksack from his back and securing vital evidence.