It took me a long time to figure out how to do this play.
For a start I couldn't quite think what the focus of the play was going to be, or how many characters it was going to have.
One of the wrong alleys I went up was thinking that I would dramatize what are called the Farm Hall Papers. This is the record that was made by the British Intelligence of the conversations of the German physicists after they had been arrested and interned in a country house in England in 1945.
It's an extremely interesting document, one of the best sources of finding out what was going on in the heads of the German physicists.
But then I thought, that's not really the story I want to tell.