They have been a blast of fresh Nordic air – Sarah Lund from The Killing, fictional Danish PM Birgitte Nyborg and ambitious journalist Katrine Fonsmark in Borgen, and Saga Noren from The Bridge being the sort of strong, multi-faceted and (crucially) more mature female protagonists rarely seen in television drama. But what future for the queens of Scandi-crime once their acclaimed TV hits draw to a close? Can Sofie Grabol (Lund), Sidse Babett Knudsen (Nyborg), Birgitte Hjort Sorensen (Fonsmark) and Sofia Helin (Noren) jump the subtitle barrier and find a wider international audience on the backs of these hit TV series? And more to the point: do they want one?
Obviously this is a very Anglo- centric question, the assumption being that these busy actors desire to follow in the footsteps of Mads Mikkelsen (Casino Royale, The Hunt) and the half-Danish Viggo Mortensen work on either British or American productions. Although they all speak fluent English, most have varied and well-established domestic careers.
But then the stars of The Killing and Borgen are beginning to crop up on British television. Last month Ann Eleonora Jorgensen, who was so brilliant as Pernille, the mother of murdered schoolgirl Nanna Birk Larsen, in the first series of The Killing, co-starred with David Tennant and met a grisly fate in the BBC2 period drama The Spies of Warsaw. And Bjarne Henriksen, who played her morose husband Theis in The Killing (and one of Birgitte Nyborg's ministers in Borgen) featured in an episode of Jimmy McGovern's BBC1 daytime drama Moving On.
Birgitte Hjort Sorensen – journalist Katrine Fonsmark in Borgen – had a guest role in last night's episode of BBC3's soldiers-in-Afghanistan comedy Bluestone 42. And actress Benedikte Hansen – who plays Katrine's older journalist colleague Hanne Holm in Borgen – made an appearance in last Sunday's re-make of Hitchcock's train-bound mystery classic The Lady Vanishes on BBC1. Hansen plays "the Baroness", one of the sinister central European co-conspirators, but she declined to be interviewed about the film, recognition perhaps that hers was a relatively minor role – the stock "dastardly foreigner". Grabol, Knudsen, Sorensen and Helin have however spoken about their futures.
"I'm not made for the world – I'm made for Denmark," Sofie Grabol told me after wrapping the final series of The Killing, in which she played Copenhagen detective Sarah Lund. "I don't really have a hunger," she admits. "I'm 44 now and I've been working since I was 17."
Despite a cameo in the 2011 Absolutely Fabulous Christmas special, Grabol has remained in Denmark, doing theatre (reprising her role in Fanny and Alexander) and starring in a psychological thriller from Danish Dogme director Soren Kragh-Jacobsen, Hour of the Lynx, in which she plays a priest. That has been followed by a romantic drama (Grabol's stock in trade before The Killing) called Det Andet Liv, which roughly translates as "second life". Does Grabol fancy a second life as an English-language actress? "I'm open, if there is an interesting role coming up from, say, the UK. Just to act in English would be something. But I'm very, very spoiled in Denmark work-wise so I've never really felt the need to conquer."
Sidse Babett Knudsen
Like Sofie Grabol, Sidse Babett Knudsen speaks fluent English, and her training in Paris and New York would seem to make the Borgen actress highly employable in international films – if that's what she wanted.
"There's something in Britain and something in France," she replies without undue excitement when I ask. But her next project is a Danish film about a woman stalking her sperm donor, in which she co-stars with Nikolaj Lie Kaas – Sofie Grabol's love interest in The Killing III.
If the success of Borgen might have turned a younger actresses' thoughts towards Britain or America, the 44-year-old Knudsen (the same age as Grabol), remains unmoved by the sort of popular culture promoted by Hollywood. In fact, when we spoke Knudson hadn't even seen any of The Killing, admitting that "I'm a bit of a snob about television".
Birgitte Hjort Sorensen
The youngest of our Scandi drama queens, 30-year-old Sorensen has already enjoyed a three-month stint in London's West End, playing Roxie Hart in the Cambridge Theatre production of Chicago. "It was some four years ago now," says Sorensen in barely accented English. "I did it in Copenhagen and they asked me to fill a gap.
"Borgen has put me on the map in Denmark, and now it's experiencing this international success I'm eager to see whether it opens any doors abroad," she says, her first foray into English-language television is on our screens this week, playing a Danish journalist, Astrid, kidnapped by the Taliban in the BBC3 bomb-disposal comedy Bluestone 42. Astrid turns out to be a sexually forward type who tries to seduce her rescuer, Nick (Oliver Chris), stripping down to her bra within minutes of her appearance on screen.
Rather more rewarding roles await in her homeland – such as the title role in director Bille August's historical drama Marie Kroyer, playing the famously beautiful wife of turn-of-the-century Danish painter PS Kroyer. "They were the It couple of the time," she says. "He was manic depressive and had syphilis, and had the mercury treatments that made him insane… Happy times."
Although The Bridge's Swedish star, Sofia Helin, was thrilled they cast a 40-year-old actor as Saga Noren, she would have preferred the role of leather-trousered, socially graceless Malmö policewoman to have gone to an older actress. "It would have been so interesting if Saga were 55 instead," she says. "I think it is so frustrating to deal with this problem [of older women's invisibility on TV] all the time. I wish our business was bigger than this."
Alas not, and as Helin heads off to play a mountain climber in a Norwegian film, the new Anglo-French re-make of The Bridge has re-cast her character with 29-year-old Birdsong star Clémence Poésy.