But the investigation received a serious setback when it was discovered the CCTV cameras on the bus that blew up were not working so detectives will not get vital images of the bomber.

One senior Yard source said: "It's a big blow and a disappointment. If the cameras had been running we would have had pin-sharp close-up pictures of the person who carried out this atrocity.

"We don't know if the driver forgot to switch them on or if there was a technical problem but there are no images."

The bus had four cameras - one covering people getting on, the second at the exit doors and one on each deck scanning the length of the vehicle.

end Mirror snip

I assume, from press reports, that these cameras carry tape and do not transmit directly to remote locations where police view action (and do their own taping) in real time.

If so, I wonder whether the tape in the bus cameras would have survived the blast. However, it is more than odd that the cameras in bus were not functioning on the morning of 7/7.

This is classic and obvious op control. Turn off the cameras. Leave no visual evidence.

That the police would regard these non-functioning cameras as merely strange and sad is also a classic reaction. It speaks of a naive level of ignorance that is massive. Of course, I'm sure there are London cops in the ranks who assume turning off those cameras was pure op control. And at the top of the London police, there are certainly men who are issuing releases they know to be false.

If you were a cop, what would you think? A bus is blown up, killing and maiming many people. Your first line of investigation on that day is the bus cameras. They didn't work. They were turned off. Would you shrug your shoulders and decide it was all a coincidence?