Betrayal, in one form or another, is at the very heart of the world of intelligence.

The composer Stravinsky had written a new piece with a difficult violin passage. After it had been in rehearsal for several weeks, the solo violinist came to Stravinsky and said he was sorry, he had tried his best, the passage was too difficult, no violinist could play it. Stravinsky said, 'I understand that. What I am after is the sound of someone trying to play it.'

The logic of war seems to be if the belligerent can fight, he will fight. That leaders will not surrender until surrender is academic. How is a national leader to explain the sacrifice of so much for nothing?

Betrayal, in one form or another, is at the very heart of the world of intelligence.

The first rule in keeping secrets is nothing on paper: paper can be lost or stolen or simply inherited by the wrong people; if you really want to keep something secret, don't write it down.

The first rule in keeping secrets is nothing on paper.

I find myself being quite cynical - and I think we all kind of are - towards the idea that it's associated with being a musician; you know... the kind of rock-star attitude. So, I hope that people know it's a joke.