Few devices in film and television are as enduring as the “odd couple handcuffed together”. Think Hitchcock’s The 39 Steps, Sidney Poitier and Tony Curtis in The Defiant Ones, or Bob Hoskins sawing cuffs off a cartoon Roger Rabbit. It has been parodied and recycled – and yet, as Sky’s new show Prisoner makes clear, the idea of being stuck with a stranger still packs a punch.

In Prisoner, the odd couple are Amber Todd, a prisoner transport officer played by rising star Izuka Hoyle (Boiling Point, Big Boys) in her first leading role, and Tibor Stone, a contract killer played by French star Tahar Rahim (The Serpent, The Mauritanian). It is Todd’s job to get Tibor to his high-profile court hearing at the Old Bailey. But when their convoy is ambushed, they’re forced to flee a relentless crime syndicate. The result is a propulsive six-parter with plenty of twists, turns and handcuffed fight scenes.

I meet Hoyle and Rahim at a hotel in London, and immediately confess I’m disappointed they’re untethered. “That would be good, wouldn’t it?” Hoyle laughs, her warm Scottish accent instantly disarming.

The pair tell me that shooting Prisoner involved eight hours in handcuffs each day (mercifully not during lunch). Alongside filming, they had to rehearse stunts. Or at least the ones they didn’t learn in “the week that got out of hand”, as Hoyle calls it. That week – the one before filming began – was the first time the pair met.

“There was no getting-to-know-you dinner, no sit-down,” says Hoyle. “Just a hello, now let’s put the resistance band on and try to roly-poly together. That’s what they made us do!”

“We bonded,” Rahim smiles. “We have no secrets now.”

“I had to figure out how my character moved,” Hoyle says. “Tahar’s character is a contract killer, so his fighting style is informed by his training. Amber is not a fighter.”

Rather, she is a new mum, six months postpartum. I tell Hoyle that as a new mother myself, I couldn’t help but nitpick: how has this character got so much energy, and why isn’t she leaking breast milk? (“I did suggest that!” Hoyle adds.) But Amber’s rage? I recognised it. I expect many new mothers will.

“I called up all my friends who were new mothers and interviewed them until we were blue in the face,” Hoyle says. “They’re tender talking about their kids, but as soon as I asked them to put themselves in Amber’s scenario, separated from their child, they changed. This animal turned up, and I’d wonder: ‘Where did my friend go?’

“You hear of women lifting cars to protect their children. That was the anchor for my character.”

The handcuff device feels so potent right now. All over the news, we hear that social media has left us unable to connect. Experts say that if we were forced to spend time with a stranger, we’d learn to get along. Handcuffing is the most extreme version of that.

“Very good point,” says Rahim, in his low, controlled voice and soft French accent. “My character is reshaped: he changes from a bad man to … I wouldn’t say good. But a different man.”

This feels like a suitable moment to mention that Rahim can be quite intense. He’s not rude or cold; far from it. But you can tell when something truly speaks to him. He can turn on a dime: one minute chuckling with Hoyle, the next stopping you in your tracks with a look. He does it in his films, and as I learn, he does it in real life, too.

The first time I see it is when we turn to his career. We’ve covered his first co-executive producer credit on Prisoner (“It all started with a frustration – I would talk with directors and when it comes to the editing room, bye-bye”); and his decision, given his Algerian heritage, to refuse stereotyped terrorist roles. But, I tell him, it seems to me every generation has a crop of French actors making the crossover to the anglophone world. In my teens the names were Vincent Cassel, Audrey Tautou and Marion Cotillard. But that seems to be happening less. Rahim is probably the most notable, alongside Léa Seydoux.

Leaning forward and almost in a whisper, he explains his opinion on success: “You just got to take it.”

He recalls the moment he decided he would indeed take it. He was at Cannes, surveying the room. “I can’t explain it, but I just felt it was time to try it abroad.” His agent tried to dissuade him, telling him he was doing very well in France. “But the biggest inspiration I’ve ever had is the New Hollywood,” he says (the 1970s movement that gave us Scorsese, Kubrick, Nicholson, De Niro). “I grew up with these movies, and that happened because I didn’t feel represented in French films.” And so Rahim packed a bag and headed to Los Angeles. He did meetings for a few weeks, and then, just when he was telling himself it was never going to work, “the next day, literally, I had two different offers. Mary Magdalene” – the biblical drama in which Rahim plays Judas Iscariot alongside Joaquin Phoenix and Rooney Mara – “and The Looming Tower”, a political drama about the FBI-CIA rivalry.

After that came his role as the serial killer Charles Sobhraj in The Serpent; an innocent Guantánamo detainee opposite Jodie Foster in The Mauritanian, which earned him Golden Globe and Bafta nominations; and, more recently, a part in Ridley Scott’s Napoleon.

I see Hoyle listening intently. Alongside the Bafta-winning Big Boys and the acclaimed Boiling Point – in which she plays a French chef despite not speaking a word of French – her CV includes Mary Queen of Scots opposite Margot Robbie and Saoirse Ronan, and Persuasion alongside Dakota Johnson. Which is why last year she was named Screen Daily’s Star of Tomorrow. In an interview she gave at the time, she said she could “feel herself getting braver”. What did she mean?

“You need vulnerability to be brave on set, to put yourself out there,” she says. “That took time. I’m finding my voice more. Trusting my instincts.”

Being handcuffed to Tahar Rahim all day certainly helps that education, I say.

“When I talk about getting braver, he’s a prime example. He’s fearless,” she says. “He completely surrenders to his work. His eyes change when the camera rolls. To be handcuffed to that, to watch it up close – I learned so much, and felt it too. It was like a spiritual experience.”

Rahim looks moved. “That’s … that’s so nice,” he says, taking her hand.

I can’t speak to the bravery of acting, but having followed Rahim’s career for some time, it is a word that comes up in discussions of his work. Particularly when it comes to his stance on Palestine. Rahim has signed several open letters in support of Palestine, including for Artists4Ceasefire – an initiative that has proved contentious in Hollywood. Some say it oversimplifies the war and risks veering into antisemitism; others that it is too cautious.

“Can I just say, it’s not about politics or ethnicity or religion, it’s just …” he pauses, choosing his words carefully.

“I just think: go back to that little piece of flesh in your chest, and talk to it,” he says. “You’ll have the answer. It’s all about humanity. It’s just not right.”

I turn to Hoyle to talk about life off set. She speaks about taking a break after Prisoner, something she had to give herself permission for. But Rahim is staring at me.

“Sorry, I just want to come back to Palestine,” he says, “that it’s brave to speak about it. It’s absolutely wrong to support a genocide. We’ve talked about Hollywood but there are other places where it’s controversial. One day I heard an important man say, ‘humans give awards, God gives rewards.’ That man was Denzel Washington. People need to be truthful.”

The room is quiet now. I break the silence and turn to Hoyle. I ask her about her name: it’s listed on Wikipedia as Chantelle Izuka Hoyle.

Her upbringing was quite different to Rahim’s. She is of mixed heritage, Nigerian and Scottish. “I was raised in Edinburgh. With the exception of my mother, all of my family were white, and at my school it was just me and a few others who weren’t,” she says.

But, she says, dropping Chantelle to go by Izuka was never meant as a statement. “I didn’t understand the gravitas; I just thought it was a beautiful name.”

This seems to have tickled Rahim and he is now laughing away. “You mean I have played next to Chantelle?!” he jokes, making Chantelle sound as French as possible. Now the pair are exchanging the sort of French phrases someone might learn on Duolingo (“Comment ça va?”).

And now our time is up. Turns out they didn’t need the handcuffs after all, I reflect as I leave the hotel. Some pairings just hold all on their own.