Rewind a decade, before Brexit, Trump, Covid and Ukraine; before social media turned politics into a global screaming match. In 2012, the box-set middle classes were engrossed in Borgen, besotted with the fictional Danish prime minister, Birgitte Nyborg. Glamorous yet vulnerable, principled but cunning, she was liberal democracy’s thrilling new torchbearer. We watched her struggle to reconcile power with family life, admired cool Danish interiors, learned about coalition government (just as we’d elected one of our own) and how to pronounce hygge.

When we left Birgitte almost nine years ago, she was divorced and politically battle-scarred, yet the party she founded – the thrillingly named New Democrats – was back in coalition, and she was heading to the Statsministeriet as foreign secretary. After that, Sidse Babett Knudsen, who played her for three series, was emphatic: bye, Birgitte.

Yet, lavished with Netflix cash, Borgen is back. So is Hillary Clinton’s favorite show, which portrays politicians not as idiots (The Thick of It) or monsters (House of Cards) but flawed idealists, still relevant in our angry, polarized age? Borgen’s creators have a record of spooky prescience: Helle Thorning-Schmidt became the first female Danish prime minister a year after the first episode. And this series has Denmark in conflict with Russia after oil is found in Greenland. As for Birgitte herself, she’s unhappily working for a younger female PM (Thorning-Schmidt coached the actress who played her on how to command a room), who looks uncannily like Denmark’s 44-year-old PM, Mette Frederiksen.

I meet Knudsen in Copenhagen, where I interviewed her a decade ago. Back then she had wild hair, a leather biker jacket, chunky boots, and was perpetually dying for a fag. Now 53, with a series of Hollywood movies behind her, she’s sleeker in a floor-length yellow wool coat and mechanically chewing Extra gum, as she’s trying to quit even Nicorette.

“I’ve never had performance anxiety before,” she says of her return. “But this part had become a kind of myth around me. No matter what I’ve done since, journalists in every country asked, ‘So is there going to be another series?’ My initial response was, ‘Don’t touch it.’ I’ve always felt very responsible for Birgitte, and the whole DNA of Borgen.”

Everything was new: the set, production company, most of the cast (including the actor playing her son). “But the first day of shooting was so great,” says Knudsen. “All at once I knew Birgitte’s thoughts, how she would react. I was almost laughing. It was a joyful thing.”

Knudsen leaves the politics in Borgen to its award-winning creator, Adam Price, a self-confessed policy junkie. But she’s always had input into Birgitte’s personal side, once arguing, in vain, against a clumsy plotline in which the drunken PM slept with her government driver. This time she wanted to ensure a truthful depiction of a fiftysomething Birgitte.

Borgen is back. So is Hillary Clinton’s favorite show, which portrays politicians not as idiots (The Thick of It) or monsters (House of Cards) but flawed idealists.

It felt odd, she says, often to be the oldest person on the set. “I definitely find myself sometimes looking for the adult in the room and then realizing, I’m the adult now.” On the plus side, she cares less about others’ approval: “No one’s around to give you a medal. You’re the one giving out the medals now, so you might as well award one to yourself.”

We find Birgitte alone: her husband has remarried, her daughter lives in New York, her student son is just an occasional lodger. Liberated from caring for others, she no longer seeks a work-life balance. She just works. This is a fantasy of many working mothers, says Knudsen. “She thinks, ‘Great, I don’t have to cook …’ I don’t know a professional woman who doesn’t secretly wish for no distractions. You assume your work will be better, which is not always the case.”

Knudsen never talks of her own relationships: she’s unmarried (never takes a date to premieres) and has a son, Louis, aged 18. “When I gave an interview early on, I told a journalist I didn’t want to talk about my private life. He said, ‘Well, we make you. So if you don’t give us something, we’re not going to give you a career.’ And I just thought it made no sense that to do my job, I should give you my kidney? Or my firstborn child? Or my secret? No way. That’s not the deal. If I’m not good at what I do, I wouldn’t get jobs. That’s the deal.”

The new season of Borgen is set in a post-pandemic world.

She was keen, however, to put her own experiences of menopause into Borgen. Birgitte, who has had breast cancer, is told by her doctor she can’t take hormones, so is constantly using a hairdryer on the armpits of her shirts after hot flushes. I say that at 53, she would surely be over the worst. “I don’t know,” says Knudsen. “I’m still on hormones. I wouldn’t let them go. I think it’s right. I do have a friend that was in the same situation as Birgitte. But for me, it’s really been a miracle.”

She hadn’t intended to take HRT; considered it akin to the debate on pain relief in childbirth, “where you either do it the natural way or they put medicine in you, and you cheat yourself and you’re not a real woman”. But in her late forties, visiting France, where she lived for six years, Knudsen confided in a friend that menopause was disturbing her sleep. The friend took her to French pharmacies where many drugs don’t require a prescription and rubbed her with her own estrogen gel. “I said, ‘Stop it, I’m natural.’ ” But back in Denmark, she saw her doctor.

It was important to Knudsen that Birgitte’s menopause was “a theme, not a plot point”, i.e., something she endured but didn’t prevent her doing her job. “We had discussions about the emotional side. I’ve had hot flushes in meetings. It’s embarrassing. Birgitte also gets angrier than she would if her hormones weren’t pushing her as well. So there’s a little loss of control.”

Menopause is part of a wider theme of whether humans can, or should, control nature, says Adam Price. Greenland, with just 56,000 people, is independent of Denmark apart from in foreign policy, defense and if valuable natural resources are found. Then the split of revenue must be negotiated between the two states. Uranium finds were a major Greenland election issue, with the country eventually voting for a mining ban. A major oil discovery would give its indigenous people, who suffer dire rates of poverty, alcoholism and suicide, the chance of prosperity and true independence. Yet this would collide with far wealthier Denmark’s zero carbon targets.

Like other western nations, Denmark has recently begun to confront its colonial past. Yet Greenland is not a far-flung domain like India or the Caribbean, but a close neighbor. Recently, Mette Frederiksen apologized and gave reparations to surviving victims of the “Little Danes” experiment where, in 1951, 22 Inuit children were taken to Denmark with the idea of educating a ruling Greenland elite. Although supposed orphans, many had families. Having forgotten their native tongue, they returned forever alienated from their communities. Many died young.

I ask Price if Denmark’s sense of itself as a liberal paragon is fading now that the country is sending back Syrian refugees and has expressed interest in Boris Johnson’s Rwandan processing scheme. “Definitely,” he says. “And we have been criticized internationally for that, not least because our image was as this very open, welcoming country. Then we woke up to internal problems of integration. We just have to admit that there are areas in Denmark with ghetto-like communities, where there’s too great a difference from the rest of the Danish population.”

The Danish realm has been shrinking since 1864, when Prussia and Austria took Schleswig-Holstein. It once included huge tracts of Sweden and all of Norway. “We come from a culture of defeat,” says Price. “We’re just the small, cosy country that tries to go about our business without making too much noise or we’ll be beaten by greater powers around us.” The Arctic territories it controls via Greenland make it prey not just to Russia but China, which seeks to exploit new, shorter shipping routes as ice fields melt.

Yet, says Price, for all this global angst the pandemic proved Danes still have great faith in their political system, with around 75 per cent approval rating for the government’s handling of the crisis. “We are sometimes sick of our politicians, but we are still near the top of the Transparency International index as among the least corrupt nations on the planet.”

Denmark was the first EU country to drop all Covid measures, on February 1, and Borgen is set in a post-pandemic world. Knudsen was at the end of one of her occasional six-month breaks – “I’ve always done these travels or pauses, to recalibrate, to think” – when lockdown began. She spent the pandemic in Copenhagen and was “very, very grateful for being here. Because we were always allowed to walk out. There was distance, but we’d meet in the park on opposite benches.” The hardest thing was keeping her mother at bay. “I had to stop her coming up to us. ‘Stay over there!’ She thinks she’s invincible.”

It was important to Knudsen that Birgitte’s menopause was “a theme, not a plot point.”

Her schoolteacher mother and photographer father raised Knudsen in Copenhagen, apart from time in Tanzania when her parents did voluntary work. At 18 she headed to Paris where, despite not speaking the language, she blagged her way into drama school. Returning to Denmark she worked mainly in theater and art house films, including with director Lars von Trier. But Scandinavian actors, like Claes Bang, Alexander Skarsgard and Mads Mikkelsen, know they must seek their fortune abroad. Denmark only makes around 20 feature films a year.

Borgen gave Knudsen an international profile: she had a major role in Westworld, played opposite Tom Hanks in A Hologram for the King (in which she filmed a sex scene on the day they met) and was a lesbian dominatrix in Peter Strickland’s The Duke of Burgundy.

The Danish show helped raise Knudsen’s international profile, which led to her role as a lesbian dominatrix in Peter Strickland’s The Duke of Burgundy.

I ask if #MeToo made her reflect on things she’d tolerated from men earlier in her career. “No,” she says. “The people crossing my boundaries have mostly been women.” Female directors in Denmark, England and France have, she says, exploited a faux-sisterly bond to seduce her into “something that I’m not comfortable with. Like, for example, only women directors have asked me to take off my clothes. Kind of insisted on it. I had to do a swimming scene and said I want to be covered. Then they gave me a small bikini. And I said, ‘No, I said bathing suit.’ She [the director] said, ‘Come on…’ A man would never dare say, ‘Come on.’ ”

Did she refuse? “Yes. But it was very, very difficult. And they get upset.” In another film she was told she’d be shot in the bath. She asked what she’d be wearing and the director, believing she’d go naked when the moment came, refused to tell her. So before the scene she sat fully clothed in the bath. “I said, ‘What are you going to do about that? Does it fit your story?’ ”

When she watches other actors in nude scenes, “I think that’s what that person is like for real. And I say the actor’s name in my head. I don’t say the role. A role goes with a costume.” She recalls a sex scene in an old series of Borgen, “and Mikael [Birkkjær], who played my husband, said, ‘No one wants to see these old bodies any more! Leave us alone!’ ” She laughs, then tells me I must write, “To my surprise, Sidse Babett Knudsen did this whole interview in the nude.”

“The people crossing my boundaries have mostly been women.”

But isn’t it positive to see more mature bodies in the sack? “Yes, maybe,” she says. “I really miss seeing romantic films with grown-ups. But a film with a woman my age is about ‘finding herself’. It is about being this age.” She gives a heavy sigh. ” ‘Oh, isn’t she liberated for having fun at tango every Tuesday night?’ That’s really sad. Why not a really sexy, passionate love story with people in their fifties or sixties?”

She looks far younger in the flesh than in Borgen, where the camera unsparingly reveals every wrinkle and fold. Knudsen says she’s never learned the skill acquired by Hollywood stars to use the light to look younger. “I think my muscles in my face are different when I’m me. I think when I’m Birgitte, her worry and her responsibility kind of dry her out in some way. What is really great is that the age issue is in there. So I don’t have to hide it.”

Birgitte is shown baffled by social media, while the younger new PM cannily fuels her popularity with selfies. Knudsen is averse to invading her own privacy. “Although I sometimes think, ‘Come on, I can’t be a dinosaur. I have to deal with this age.’ ”

The stark generational divide between complacent fiftysomethings and their progressive children is one of Borgen’s new themes, with Birgitte’s son joining vegan activists at war with Denmark’s pig farmers. “Why don’t you just do something,” she rails at his pious girlfriend, “instead of playing the victim game all the time?” Adam Price says this comes from arguments he has at home with his 26-year-old vegan medical student daughter: “All this demonstrating climate change by not going to school, like Greta Thunberg? I say you can’t only be activists by being absent from things.” Knudsen agrees. “I definitely think it is so much easier to tear down than to build.”

Alongside the old pressure of fame is a new expectation to be a spokesperson for every cause, but Knudsen is wary of a new intolerance. “It’s like if you’re not with us, you’re against us. So if you don’t approve of this message, you disapprove of that message. Which is not the case.” She thinks it ironic that “on one hand we are trying to push off all boundaries, and have much more colors on the palette of sexuality and gender and identity. But at the same time you’re not allowed to change your mind, to be searching, or not knowing. Judgment. Judgment.”

Given this explosive, opinionated, activist age, there is more need than ever for political drama. So is this series of Borgen a one-off? Will we see a Prime Minister Nyborg command the Statsministeriet again? Netflix has deep pockets. “Never say never,” Adam Price tells me. But Sidse Babett Knudsen shakes her head. “No way. Birgitte is done.”

Season Four of Borgen is streaming now on Netflix

Janice Turner is a columnist for The Guardian and The Times of London