The threat of a terrorist attack using nuclear weapons is "real and imminent", the head of the UN's nuclear watchdog said today. Mohammed al Baradei, chief of the International Atomic Energy Agency, said it was a "race against time" to prevent terrorists from obtaining nuclear materials. His words echo repeated warnings by Tony Blair of the danger posed by an alliance between rogue states and terrorist groups such as al Qaeda. Mr Baradei raised the spectre of terrorists being able to assemble a "dirty bomb". He said there was a real risk of uranium or plutonium falling into the wrong...