Agyness Deyn: I'd never swap gruelling Hard Sun for a fashion shoot

“But this song about the end of the world isn’t what you might expect,” adds the British writer who has long been based in New Zealand. “It isn’t some grinding rock song that’s bleak and nihilistic. It’s huge and it’s epic and weirdly life-affirming. And that was the inspiration for Hard Sun.”

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Cue the high-concept crime/sci-fi BBC drama that is set in the present day but has as its backdrop and overarching theme an “extinction-level event” involving an overactive sun. At its heart, though, is a pair of grimly mismatched London coppers, one male and one female.

“I wanted to create a female lead unlike any other on TV,” says Cross. “When men write a female lead there’s a tendency to write the Cool Girl – a fetishised ideal of what a man sees in a woman. I wanted to avoid that trap. I wanted to write someone who was just herself.”

That process resulted in Elaine Renko, who is described as “tomboyish” in an early script. “Like so much of the DNA of this show, that androgyny emerges from Bowie. I just loved how naturally he played with gender stereotypes.”

Enter Agyness Deyn. The former model from Lancashire had a decade-long run as a supercool It Girl, the face, among others, of Burberry and Mulberry, and British Fashion Awards Model of the Year 2007. Then in 2010 she made the switch from fashion to film and, switching professional gears, cut her teeth in a succession of indie/arthouse films (Pusher, Electricity and Terence Davies's adaptation of Sunset Song). Now Hard Sun is her first job in television.

When Deyn and I meet, she's halfway through the six-month shoot. We’re in a studio in east London, where she’s been working long days, doing most of her own driving and fight stunts. “The first time I read the script, I was like, ‘Holy s**t. I need to play this woman," the 34-year-old says. "I don’t know where that [impulse] lives in me. But I have to figure out how to do it.’”

Deyn mainly lives in upstate New York these days with her second husband, hedge-fund manager Joel McAndrew (her first marriage, in 2012, was to the actor Giovanni Ribisi, who appeared in Friends as Phoebe's brother). But she readily flew to London to audition. Then, having got the role, she threw herself into the preparation, which included being trained in boxing, krav maga and Korean stick-and knife-fighting. She was taught the latter by a 5ft South American woman, “and God she could fight. I used to do competitive karate as a kid, but she was just amazing. She and her husband were training me and she was kicking his arse.

“It doesn’t matter how small or how perceivably weak you might look,” she continues. “It’s about precision and intellect and the mindset. And that was my first ‘in’ to the character.”

Mid-filming, Deyn looks comfortable with her character's appearance. It’s a no-fuss look that chimes with Cross’s determination to avoid the “will they, won’t they” sexual chemistry that hobbles many a cop duo.

“When Neil and I talked about her, I thought she was quite monk-like. In the whole series she has two outfits. We decided she was someone who doesn’t give a damn about her appearance or what people think. And she has a simplified life to enable her to have this extreme focus. In one of the scripts it said her beauty regime was ‘sticks her head under the tap, splashes her face and she’s out’. She’s not dirty,” Deyn clarifies with a gutsy laugh. “But she’s here and she’s focused.”

Is Deyn prepared for the new kind of scrutiny that will come with a TV role at Peak O’Clock? “I haven’t really thought about it like that, to be honest,” Deyn admits. “Yeah, more people will see it than the independent films. But I feel like your next job is your next job. And Renko was the woman for me.

“I experienced being in the public eye in my twenties, so now all I want to do is be really bloody good at my job. It’s only now I’m realising, ‘Oh wow, it’s gonna be on telly!’”

Before she goes back to set, to film more bruising stick-and-knife fights, I wonder: have there been any moments in this gruelling shoot when she’s found herself craving a nice easy fashion shoot?

“No way,” she says with a wince of relief. “No chance. Doing this is so physical, and so exhausting, but it’s so alive. I’m living the whole character, the whole skin of Renko. That’s what’s exciting.”

Hard Sun begins on Saturday 6^th January at 9pm on BBC1