I'm an eternal realist and the success rate for being an actor is pretty low.

Our job is to represent the truth of human nature, whether you're playing a tender love story that's set in a coffee shop or whether you're in 'The Avengers,' which is set in a Manhattan which is exploding.

It was quite a European war until 1917, when the Americans joined up. They don't have the same sense of the loss of innocence and the cataclysmic loss of life. A whole generation was wiped out.

I always found the extraordinary loss of life in the First World War very moving. I remember learning about it as a very young child, as an eight- or nine-year-old, asking my teachers what poppies were for. Every year the teachers would suddenly wear these red paper flowers in their lapels, and I would say 'What does that mean?'

I did a production of 'Journey's End,' an RC Sherriff play about World War I, at the Edinburgh Festival. I was 18 and it was the first time that people I knew and loved and respected came up to me after the show and said, 'You know, you could really do this if you wanted to.'