At 84 years of age, Sir Charles Mackerras is one of the best-respected and best-loved operatic conductors working in the world today. He conducts Benjamin Britten's The Turn of the Screw for the English National Opera tonight and, despite bouts of ill health, found time to talk about his friendship - and falling out - with Britten, his time conducting the opera under Britten's watchful eye, his experiences in Prague in 1948 as a witness to the Communist takeover of Czechoslovakia, his pioneering performances of Mozart from the 1960s and his run-ins with Richard Jones and Christopher Alden over their "monstrous" modern productions.