Thelma Schoonmaker is arguably the world’s most famous film editor, winning three Oscars in her 40-year career. Ever since Raging Bull, she has worked on all of Martin Scorsese’s major feature films like Goodfellas, Gangs of New York and Killers of the Flower Moon. She tells Francine Stock some secrets of the cutting room and about the other director in her life, her late husband Michael Powell, himself a major influence on Martin Scorsese.