The first series of Peaky Blinders was described as the 'anti-Downton', and no wonder, given its early 20th century gritty gangland setting, stylistic tone and slow-motion set pieces, which set it apart from more staid period dramas.
And then there was the stomping soundtrack, which included Nick Cave and Jack White.
"I have to admit, initially I was like, 'You're putting contemporary music with a period drama?!' But it worked, because a lot of the artists had an outlaw quality to them, and that seemed to suit the essence of the show," says Cillian Murphy, who plays Tommy Shelby, the ambitious head of Birmingham's criminal gang, Peaky Blinders.
The Irish-born actor, who lives with his two sons and artist wife in London, believes the success of the show developed in the very best of ways, through word-of-mouth.
"It was only on for six weeks, but people were telling people to watch it. That's what you want, rather than things being shoved down your throat."
Wearing Tommy's sharp suit, Murphy's androgynous features and huge blue eyes make a mesmerising combination, not least when topped off with the Peaky Blinders' distinctive haircut – shaved sides and longer on top. "I was alarmed by the haircut, I have to admit, but I'm contractually obliged to have it," he confides, grinning.
The team are in the last few days of production on series two, and he's exhausted. "But in a good way," he clarifies. "I like that exhaustion that comes from loving the character and everyone on the job. It's a pleasant weariness, and I sleep like a baby."
Series one began shortly after the First World War and centred on the gang as they came into contact with Chief Inspector Chester Campbell (Sam Neill), who'd been tasked with cleaning up the city's streets. He's as morally corrupt, if not more so, than the gang, however, and at the end of the series, shot the woman Tommy had been growing close to.
"We met Tommy when he was emotionally quite distant, and a bit damaged and broken, understandably, after all his experiences in the First World War," explains Murphy, 38. "With that relationship, he did defrost a little and genuinely fell for her, so that's set him back emotionally."
Murphy doesn't mind admitting he finds the intense scenes with Neill a "great problem".
"He's a good friend and I love him dearly, but we have this hatred in those scenes, so you go from hanging out and laughing to deep vitriol. He's such a despicable character, but you can't help but love him."
In series two, time's rattled forward to the early Twenties, and an edgier "cocaine feel" has replaced the dreamy, opium-infused ambiance of the first run.
"Cocaine was widely available and popular among the upper classes, and obviously it was being distributed by the gangs, so I think that's informed the tone of the series," agrees Murphy. "Also, Tommy's moved on from that crutch of opium, although I think he's still boozing it up and has his issues."
The actor believes the writing has "stepped up". Partly because there is greater freedom when there doesn't need to be as much exposition but also because creator and writer Steven Knight has written all six episodes, not just the first two, as he did last time."
As with any sequel, Knight, Murphy and the rest of the team wanted to be bolder, so this time the Peaky Blinders venture out of Birmingham and head to London.
"It's about Tommy's ambition, and the expansion of family and their collective ambitions, which ultimately means moving south and taking on two gangs down there, the Jews and Italians. That's his path in the show," he explains.
The new series also sees the arrival of new faces, including Hollywood star Tom Hardy and (his rumoured new wife) Charlotte Riley.
He'd be loathed to give anything away about Hardy's "creation", but "suffice to say it'll be memorable," he teases.
The chance to reunite with the original cast, including Helen McCrory who plays Aunt Polly, was also a bonus for Murphy. "Helen puts in an astonishing performance this season. We see the conflict in her, being this woman and a gangster and trying to marry those two," he says, before joking that their characters' relationship is even more complicated this time round.
"She's obviously the matriarch but she's not his mother, she's his auntie. And there's not much of an age gap between them, and that causes tensions."
But she also understands him more than anyone. "So although she's a thorn in his side, she's the one person he trusts."
All credit to Knight for creating such strong female roles, and for achieving sympathy for characters who, on paper, we should detest. "None of these characters are perfect or infallible. Even though they operate in extreme environments and have moral codes we could never subscribe to, at the same time, we see their weaknesses, foibles and desires," says Murphy.
"What I like about Tommy is that, even though he's a power-hungry gangster, he's really vulnerable and broken inside. He's a man who left all beliefs behind in muddy France, any respect for authority, any faith, and came out a man who fundamentally isn't afraid to die. And that's a great thing to play, because it informs everything. It's not nihilistic, it's fearless."
Murphy, who grew up in Cork and played in bands before focusing on acting, achieved mainstream success in Danny Boyle's 2002 movie 28 Days Later. He's gone on to appear as Dr Jonathan Crane, aka The Scarecrow, in Batman Begins, Jackson Rippner in Wes Craven's thriller Red Eye, a transgender in Breakfast On Pluto, and more recently, the heir to a fortune in Inception.
"I've always been interested in playing characters that are, if not outsiders, at least ordinary people in extraordinary circumstances," he says. "That's always been more appealing to me, and there's a happy coincidence now, as that seems to be a lot of the characters in television."
Peaky Blinders marks the first time he's returned to a character, and he hopes a third series will be commissioned.
"Steve has a plan up until the Second World War, and I love Tommy. These are the sorts of characters you search for; great, meaty, complex parts."
That said, a short break is welcome. "It'd be nice to know you're coming back, but it's also quite nice to have a break," Murphy admits. "Tommy's quite intense!"
*Peaky Blinders returns to BBC Two on Thursday, October 2, at 9pm.
