LONDON - The BBC director general, Mr John Birt, summoned by MPs before the Foreign Affairs select committee to explain plans to merge the World Service news with the rest of BBC news, was attacked last night by a former BBC foreign correspondent. Mr Mark Tully said Mr Birt thought himself "more infallible than the Pope" and "didn't give a hoot" for the views of critics like Mr Denis Healey and Dr Robert Runcie.