A DESPERATE search is under way for a “chemical vest” that a British suicide bomber was ready to deploy in a terror attack on London. Police fear that the strike, using a home-made chemical device, was imminent after an informant told MI5 that he had seen the lethal garment at the home of two young men. Last night detectives were at the hospital bedside of a 23-year-old postal worker shot during a raid on his parents’ home, while his younger brother, aged 20, was being questioned at Paddington Green high security police station. Armed officers who led the assault on...