London - Scotland Yard is to investigate whether a former MI5 agent breached the Official Secrets Act when he revealed details of bugging operations against prominent people. Mr David Shayler's revelations included an allegation that the Security Service bugged Mr Peter Mandelson, now Minister without Portfolio, for three years in the late 1970s. On Tuesday, Mr Shayler said the Security Service missed the chance to "finish off" the IRA when it was mounting a bombing campaign in England. He also said that during five years in MI5 he had checked on senior Labour politicians who might have become ministers if Mr Neil Kinnock had won the 1992 general election.