In America, he is known almost exclusively as the evil Emperor Palpatine from the Star Wars films. But Ian McDiarmid is one of British theatre’s respected eminences, and he sees his role in one of America’s dominant pop culture phenomena as an interesting sidebar, but hardly the signature moment of his career. Still, the role seems to have grown on him, in all its one-dimensional glory. “I thought Palpatine was a pretty good character. I like the notion that he didn’t have any psychological subtlety or depth, that he was just solidly evil and the dirtiest word in his vocabulary was ‘friend’. I thought that was terrific.”