Byline: EXCLUSIVE by JEFF EDWARDS and CHRIS HUGHES
SCOTLAND Yard launched Britain's biggest ever manhunt yesterday to catch the London bombers - vowing: "We will go to the ends of the earth to nail these coldblooded killers."
And troops from Britain's most secretive army intelligence unit - the Special Reconnaisance Regiment - will join them.
More than 1,000 police staff were assigned to the case. Metropolitan Police Commissioner Sir Ian Blair said: "We will not rest until we find them. We will be relentless."
Senior Yard sources said: "It will be the biggest, most intensive and focused investigation in British policing history."
British Transport Police have recovered nearly a million used tickets from barriers across the rail network, hoping some will carry the bombers' fingerprints as they travelled into London.
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.
But the anti-terrorist squad are confident that other CCTV footage will help nail the three other terrorists.
Senior sources at the Yard said they were seizing film from an estimated 2,000 cameras in the biggest operation of its kind.
Film from every Tube train and station will be examined as well as footage from the 12 main line termini and scores of platform cameras and trains across the British Rail network.
Scores of street traffic cameras and those protecting banks, businesses and shops may have picked up the bomber when he boarded the No 30 bus somewhere along the double-decker's route.
Anti-terrorist officers were examining the bus and the wrecked carriages of the bombed Tube trains.
After the injured and dead were removed, explosives specialists swabbed the scene - including victims' skin and clothes - with chemicals to find out what kind of high explosive was used.
Teams of evidence recovery specialists will sift through thousands of pieces of wreckage for even the most minute bomb parts, hoping to build accurate model of the bombs.
Even pieces of fabric will help reconstruct each sports bag or rucksack they are thought to have been carried in.
Meanwhile, other teams will scrutinise hundreds of hours of CCTV footage and speak to hundreds of people who were on the Underground at the time. These will include even the most seriously hurt because it is thought they were the closest to the explosions and may have seen the bombers.
Intelligence analysts from the Special Branch and security services will comb hundreds of computer records of surveillance logs, phone and email intercepts and other information to see if important pointers to bombers was overlooked.
The information will be compared with CCTV images of people carrying similar bags to help identify the culprits.
Andy Hayman, the Met's Assistant Commissioner and terrorism co-ordinator, said: "The bombers are all certain to have been caught on many cameras during their journey to and on the Underground.
"They were not masked so we will end up with very good pictures that will identify them. …