Improvised device could have caused more fatalities than 7/7 attacks
Counter-terrorism specialists were last night carrying out detailed forensic analysis on the Parsons Green device, as experts said it could have caused more fatalities than those used in the 7/7 attacks in London in 2005.
The improvised explosive device, which was contained in a 10-litre plastic bucket, exploded on a District Line tube, as hundreds of commuters made their way into the centre of the capital.
But mercifully, thanks to the incompetence of the bomber, the main explosive charge failed to go off when the device was prematurely activated as the train sat at Parsons Green station in west London.
The bomb was contained in a white bucket, which was disguised in a plastic cool bag from the supermarket, Lidl.
It also appeared to have been covered with a black cloth, perhaps to try to mask the smell from any chemicals contained in the bucket and disguise what was inside.
Images of the device, taken by quick-thinking passengers, showed a string of Christmas fairy lights protruding from the top of the bucket, which one expert suggested could have been used as part of a crude timer mechanism.
The lights, which would be attached to a battery and could be set to flash intermittently, would be used to deliver a charge into the detonator.
Theoretically the bomber could have set the lights to flash on a delay, giving himself a short window in which to escape before the device detonated. But it is thought the detonator, usually made up of volatile materials, burst into flames prematurely, perhaps as a result of friction within the device caused by the moving train.
David Videcette, a former Met counter-terrorism officer who investigated the 7/7 attacks, said the IED appeared to have many similarities with previous devices.
He said: "In terms of scale this is bigger than the devices used in 7/7, so had it gone off successfully it would have caused huge loss of life.
"Whoever built this was not an amateur - it has many of the hallmarks of devices used by terror groups, but the use of the timer to set off the initial part of the device is something we have not seen before in the UK."
Fortunately the fireball from the detonator did not set off the main charge, possibly because the bomber failed to get the correct mix of chemicals needed in order to complete the chain reaction needed for an explosion.
Will Geddes, a terrorism expert, said: "My suspicion is that Parsons Green was not the intended target. Unless a person knows it, it is not going to mean a great deal to you - if it was Paddington or Notting Hill, they are internationally recognised names."
Sources said the bomb was packed with shrapnel, including nuts, bolts and nails to cause maximum devastation when it exploded. (© Daily Telegraph, London)