SECURITY sources believe that a man arrested in last week’s anti- terror raids in Britain is Al-Qaeda’s leader in this country. Home Office officials say that one of those arrested is suspected not only of masterminding the foiled plot to bring down up to nine transatlantic airliners, but also of involvement in other planned atrocities over the past few years. They believe that he was instrumental in sending the ringleader of at least one previous British terror plot for training at a camp in Pakistan last year. He is described by counter-terrorist officials at MI5 as the senior figure in...