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.

When you're watching, I find two things happen. You either watch a film and it's really good and then you think, "Why can't I do that?" Or you watch a film and it's not good, and you think, "Why am I doing this?" So either way, it feels like being at work.

The story [of Allied ] itself is the story I wrote, and that's what's great about Bob [Zemeckis ]. You have meetings, but it's meetings for clarity, not to change what they're saying or doing. He takes what's on the page and executes it so brilliantly.

I visited the set [of Allied] a few times, and it was a great set to visit. A lot of it was in West London, in an old Gillette factory. You'd go into the factory through the security, and then there were a lot of camels and goats. Most sets are really dull, but this was fantastic.

A commission and an original are two different things, and both have their virtues and vices. A commission is a bit more collaborative, in that you outline the story that you think should be told, and then you write it.

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.

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