Sienna Miller on NYPD training, under-sharing, and why British crisps are the best

Of all the things Sienna Miller learned while training with the New York Police Department for her latest film, 21 Bridges, it’s not necessarily the SWAT skills that stuck with her most.

One of the most memorable things, the British actress tells Sky News, is the made-for-the-movies language.

“I had to [learn] how to move like a cop, how to clear a room, how to move tactically into a space where there could be, what the NYPD call – ‘bad guys’,” she says, switching briefly to the broad New York accent she pulls off in the film. “Which I did find funny. They actually do call them the ‘bad guys’.”

Also starring Chadwick Boseman, now best known as Black Panther, 21 Bridges is a gritty New York cop thriller of the “old-school” ilk Miller grew up on, like “The Fugitive and Sidney Lumet movies and Heat”.

Miller and Boseman play detective partners Andre Davis and Frankie Burns, who are facing a manhunt for two police killers following a drugs pick-up gone wrong. The answer? To close all 21 bridges in and out of Manhattan.

For Miller, who plays narcotics officer Burns, it was a behind-the-scenes look into how the NYPD operates.

“It was pretty cool, you know, to look behind the curtain of that world, which feels like a very remote and quite exclusive place,” she says. “My character would have had to do drug deals and kind of infiltrate really shady situations and become part of the gangs. That part of it was an interesting thing to ponder.

“And to be a woman in what is very much a man’s world was fun. We got to train with lots of New York City police detectives and cops and hear all of the stories and have them around. And to be tactically trained as an NYPD cop is cool.

“Me and Chadwick did a lot of SWAT training and weapons training. All of it.”

So would Miller feel able to look after herself now, should she ever need to?

“I think I would. You know, your instinct is different to how you should actually be. So I think I would have a better idea of how to enter a room where there might be gunfire. Which is a useful skill, I suppose. I hope I don’t have to ever use it, but you never know.”

Working with Boseman was awful, she jokes. “He’s so boring, isn’t he? I’m kidding, obviously… he’s the kindest, sweetest human being.”

And in all seriousness, Boseman was influential in her getting the role, she says.

“He was also a producer on this film. My character was originally written to be a man, and he was very influential in changing that. I think he’s a real champion for women, and I have deep, deep respect for him.

“I think that the world is changing in a way where those kinds of decisions are being considered in a way that they might not have been before. I’m obviously thrilled that they did make that decision because then I got to be in it.”

As a mother, playing a single mother city detective made Miller think about the role of police officers in a different light.

“Obviously there are lots of things going on in the city all the time that we don’t think about and aren’t aware of,” she says. “My character is a single mother. I’d never really considered when you see a cop walking around on the street that they really are putting their lives on the line and leaving families at home and making a sacrifice.

“I think I have a much deeper respect for what that job requires versus taking it for granted. And of course, the stories that they have – if they’d been in homicide, which the detectives training me had been – are pretty astounding.”

When Miller first broke into the public consciousness in her early 20s, with her big-break films Alfie and Layer Cake both released in 2004, it was her relationship with Alfie co-star Jude Law, as well as her coveted boho style, which garnered the headlines – and lots of judgement on her private life.

Chased down the street by paparazzi late at night and a victim of the phone hacking scandal, in 2011, she gave details revealing the impact her introduction to the darker side of fame had on her to the Leveson inquiry.

It is mainly for this reason, she says, that she stays away from social media – her blue-tick official Sienna Miller account on Instagram has just one photo, posted in June 2017, with the caption: “Hello World Wide Web. #givenin #peerpressure #luddite.”

“It’s just not something I am particularly good at,” she says. “It just doesn’t fit with my character. I struggle with time management enough as it is and it just is distracting to me in a way…

“I just don’t really have that impulse to share that much with people. I don’t know. I mean, I share everything with people that I do know. But to be good at it, I think you have to be a little bit willing to share your life. And I think mine was pretty scrutinised for long enough for me to have quite a strong reaction against opening out further than I have to for my work.

“But I’m not knocking it. I think amazing things have happened as a result of it, connection between people; the Arab Spring, you think about how movements like Time’s Up and #MeToo have been able to spread in the way that they have. And that’s really because of social media.

“So I see the benefits of it. I just… no, not for me. But good luck to everyone who loves it.”

Over the past few years, the tabloid stories about her personal life have been matched, if not completely replaced, by critical acclaim for a CV of wide-ranging roles, in films such Foxcatcher, American Sniper and American Woman.

But now she is in the know about the inner workings of the police, I ask if she would be up for a stint dealing with bent coppers in TV behemoth Line Of Duty, following in the footsteps of fellow Hollywood star Brits Thandie Newton, Stephen Graham and now Kelly Macdonald, who has just been confirmed for the much-anticipated sixth series.

“Do you know what, I haven’t seen it, which is awful because I think Kelly Macdonald and Thandie are incredible. But I have been living in New York and I haven’t seen it, which is awful. But I will now. And yes, I would consider it.” She laughs. “I’ll do anything.”

Miller has been in New York for several years now, bringing up her daughter, Marlowe, with her ex Tom Sturridge. But the UK is still home, she says.

“Oh, I miss everything. I mean, I live here, but England’s home. And when I land back, I really have this feeling that I don’t have anywhere else in the world. I think I miss the most the irreverence, the humour. And, you know, a good packet of crisps, proper chocolate, a good pub and all my family and friends.”

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And so to the big question: favourite crisps?

“Pickled onion Monster Munch,” says Miller, no pause. “Then Wotsits. I love Space Raiders; a maize-based crisp would be my preference. Squares, now and then. Yeah, Skips… I really love crisps.

“You know, there’s an English shop in New York; there are two English shops, one’s called Myers of Keswick and the other one is called Tea and Sympathy, and they do have English crisps.

“So I do manage to stock up. And any time anyone visits me, they bring me Fairy liquid so that my washing can smell like home, and crisps. Fairy non-bio tablets for my laundry and, yeah, a good packet of Wotsits.”

21 Bridges, starring Chadwick Boseman and Sienna Miller, is released in UK cinemas today

(c) Sky News 2019: Sienna Miller on NYPD training, under-sharing, and why British crisps are the best