Did you have to do much research into the actual Peaky Blinders gang before you took on the role?

There's not that much written about the Peaky Blinders – there's about two or three books that touch on them, and that touch on the violence in Birmingham and the gangs that were going around in the north of England at the time. But what I did do is I spoke a lot to (program creator) Steven Knight, and he was inspired by stories that his father told him. [His father] had been sent to deliver a message to his uncle, and he was terrified; he had to go to a part of town that he'd never been to. He went down Garrison Lane and knocked on the door and went into a smoke-filled room, and saw it was an illegal betting shop. And in the room, behind the glass there were these three men drinking homemade gin out of jam jars and were wearing the most beautiful three-piece suits and peaked caps, surrounded by piles of money. And his father became obsessed with this world – he didn't ever join it, but he found out all these stories and passed them on to Steve. And so really, Steve is the person that all the actors go to to talk about these stories and he knows all these characters; they all existed. So it was through him, really. Like a lot of this history, it's passed on orally but isn't written down.

She's lethal: Helen McCrory stars as Aunt Polly in Peaky Blinders.

Despite her criminal nature, do you see Aunt Polly as a strong role model for women?

I think it's a realistic portrayal – these were very, very tough, hard-working women. They kept these families together when the men were off fighting the Great War – and then when the men came back from France, they not only had to give their jobs back but they also had to deal with men who had brought back the fields of France with them. These men were still living in hell and were shell-shocked, and no longer believed in God or government or anything else. I wouldn't say Aunt Polly was a good role model though. She's a hardened criminal badass! But she is an interesting woman to play.