'Four Lions factor': how terrorist incompetence is saving lives

Witness accounts of the “fireball” on a tube train at Parsons Green in London and the images of the bomb apparently responsible suggest an improvised explosive device that did not function as intended.Metropolitan police sources said the device only partially exploded, and initial examination of the device led explosives experts to conclude it was “viable”, meaning it was meant to explode more fully.This has happened before: on 21 July 2005, when a series of bombs hidden