I think people are drawn to characters that break the rules. I think there is something about a good person doing bad things for what they consider to be a good reason. Then the battle is on to almost prove to the audience that it's justified. How far can you go with that? How far can that character go before people won't accept it? Trying to walk to edge of that line is a challenge.

[Allied] meant to be a film that's a bit different. It's roots are in the '40s and '50s, and that sort of filmmaking style.

I'm always interested in characters who are closed down, but who open up when they choose to, rather than when they're obliged to. I think that's a very appealing thing, for an audience and just in life. I like the idea that something will say nothing, and then get straight to the point. That feels like how your heroes should be.

In other words, when you have someone [like Ridley Scott] with that authority, then you tend to be left alone. But they were good and they're really good people, and I'm a big champion of the BBC and I think that like minds find each other and I think that FX and BBC is a perfect match.

I'm very, very excited because I'm just completing Episode 6 of Series 4 [of Peaky Blinders], which again I think is the best yet. And I'm loving it and it's not like work, it's not like a labor, I love doing it, and the boys are coming back and they're loving the scripts.

I spoke to Tom's [Hardy] manager and said, "While we're talking about Taboo, do you mind if I also mention this film project that I've got, which is called Locke, and I need Tom to play the lead." And we spoke about both in that meeting and in the end the deal was that I would do Taboo if he did Locke and vice versa.

In terms of how [Allied] looks, it's fantastic and much better than I had hoped because it's so lush and so beautifully executed.