The British security official said there were similarities between the device and vehicle bombs used by insurgents in Iraq.
The official also said the domestic spy agency MI5 would examine possible connections between Friday's bomb attempt and at least two similar foiled plots — to attack a London nightclub in 2004 and to pack limousines with gas canisters and shrapnel.
One of the great concerns of anyone following the Iraqi insurgencies has been the probable diffusion of knowledge on conducting successful urban guerrilla warfare. We have seen it in Algeria, we have seen it in Jordan, we have seen it in Saudi Arabia. If we are starting to see deep strikes, or long distance networks reforming with a combination of outside expertise and local, self forming and directed groups, this process has reached another level of threat.