It has to be an actress like Marion Cotillard [in Allied] because there are so many levels to it. It's set in the Second World War, when lots of people were doing things that, outside of a war, you wouldn't do, like killing and dropping bombs. She's doing things that one wouldn't approve of, but it's war.

There [in Allied] were things that were written that were cut, and things that were shot that were cut, but if the film works, they are erased from memory.

It felt [at the Allied set] like, "At last, I'm in Hollywood," even though I was in West London. It was like, "This is how a film should be made." It was beautiful.

There's more to come. Series 4 [of Peaky Blinders] is coming soon. But I'm proud of making my hometown, which is considered to be completely unfashionable, slightly fashionable. People actually know where it is now.

You know that when you suggest something on the page, it's going to be there, plus more. It's a great luxury to know that you don't have to push it. You just lay it out, and it will be there.

I think it creates so many more opportunities and pitfalls in that you are treading on fresh snow, so you're in a new place.

No screenplay is possible, unless you get some attachment from somebody who's going to get it made.