John Byrne: 'If I don't laugh when I'm writing, it gets tossed out'
The playwright's Tennis Elbow is a gender-swapped version of Writer's Cramp, his uproarious 70s hit about a failed literary figure If you were in Edinburgh during the 1977 festival there were two shows you couldn't miss. One was the revue Beyond a Joke starring a young unknown called Rowan Atkinson. The other, down at the old Calton Studios, was a three-hander called Writer's Cramp. The exuberant comedy by first-time…