[Allied] got the attention of (director) Bob Zemeckis and Marion Cotillard. I'm glad I waited. If it had been made 15 years before, who knows how it would have looked, but it's got the best possible cast, director and everything. It's been fantastic. It was worth waiting.

[Taboo] has been exactly the same as working with the BBC in that creatively they do that precious thing which is to only make a comment when a comment needs to be made.

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.

I think certain periods of history don't get dealt with because I think historians, and it's their job, but they look back and look for patterns. They look for sequences and they look for reasons, and certain periods of history don't fit with the general pattern of 1500 to the 20th century, during which there's the creation of the United States. At this time of 1814, two nations who would eventually become close allies were at war with each other, so it doesn't quite fit.

When Brad [Pitt] responded [to Allied], suddenly what was impossible became possible, which was great. But along the way, whenever I told the story, it had an affect on people. At its core, this was an effective story.

I think that helps because there has been no formality of friendship, the politeness of friendship, so we can just work directly on the work that's ahead of us [with Tom Hardey].

I always thought it would never happen. And then, it became possible. In between commissions, I wrote it as an original screenplay [Allied].