In 1977 I interviewed Christopher Isherwood about his memoir, Christopher and His Kind. During the interview he said how much he regretted burning the diaries he had kept while living in Berlin in the early 1930s. Why? Because, he told me, they gave a much truer picture of his past than the two novels he based upon them. Instead of being an observer, in the diaries he appeared as a participant, cruising bars in search of ‘boys’, which was why he’d gone to Berlin in the first place. It was okay to admit this now, but in those days you simply couldn’t risk such compromising material falling into the wrong hands. So up in smoke they went.