All hail the women of Peaky Blinders

• Who were the real Peaky Blinders?
• Meet the cast of Peaky Blinders series four
• When is Peaky Blinders series 4 on TV?

One hooded glance, however, from “Aunt Pol” (Helen McCrory), the Midlands’ answer to Chicago’s Ma Barker, and even the boldest star-hunter ducks out of sight.

If bad, beautiful Tommy Shelby is the Sun King of Small Heath, each of the women in his orbit, from matriarch Polly to his many love interests, has her own agenda in this hotly anticipated fourth series.

“In the period after the First World War, women were incredibly powerful in working-class communities,” says series creator Steven Knight. “While the men were away at war, the workplace – including illegal gambling rackets – had been run perfectly well, if not better, by women. But when the war was over, legislation was passed saying men must once more be preferred over women for jobs, and women were quite rightly baffled by the idea they were suddenly being told not to work.

“I wanted to reflect that – and do justice to those women. Tommy, to his credit, doesn’t care if it’s a man or woman doing what needs to be done; he sees it’s in the natural order of things for smart people to make the decisions and for less smart people to carry them out. So it’s not at all surprising that, in a family like the Shelbys, strong, intelligent women would rise to the top.”

The enigmatic Tommy, Knight goes on, is shaped by feminine influence – not just the women present in his life but, crucially, the Gypsy mother he lost in childhood. “The First World War was a moment in history when a kind of pastoral culture died. Tommy’s mother, with her link to the land and horses, represents that pastoral tradition. He watched her disintegrate because of the pressure she was under, and it’s a deep scar for him.”

Cillian Murphy agrees that Tommy Shelby was, and still is, beholden to the women in his life. “All the good stuff in Tommy comes, through his mother, from the Romany side. Polly’s the one he trusts most. And he loves his sister, Ada, even though he’s frustrated by her politics. His romantic relations are less straightforward.”

That puts it mildly. In series one and two, Tommy swung between Irish secret agent Grace Burgess and horse-loving aristocrat May Carleton. No sooner did he marry Grace at the beginning of series three than she was murdered. Since then, he’s had a go at orgies and erotic asphyxiation with Tatiana, a double-crossing White Russian, and enjoyed regular hook-ups with his brother John’s ex-fiancée, Lizzie Stark.

Murphy takes a deep breath. “Right,” he says, “during the time Tommy was married to Grace he was completely faithful. Prior to that, sex was basically a way of self-medicating, then Grace’s death spun him off into something else entirely. I think that as we meet him now, he’s probably shut down again emotionally, and sex is just a physical need that has to be met.”

It sounds, and is, exhausting. “For any actor, playing one character exclusively drives you crazy. I don’t share one strand of DNA with Tommy,” says Murphy, who has two sons with artist Yvonne McGuinness. “He couldn’t be further away from me, so it’s always an effort to play him, and then an effort to shake him off.”

Bearing that in mind, would Murphy return for a fifth series? His steel-blue eyes spark up. “You’d be an eejit to want to walk away from something as good as this.”

Peaky Blinders returns Wednesday 9pm BBC2