As television goes, the stakes could hardly be higher. The jewel in the crown of the BBC's spring programming, six hour-long episodes in the prime Sunday-evening slot and, what's more, from a book by John Le Carré. It's half a lifetime - nearly 40 years - since Tinker, Tailor, Soldier, Spy and Alec Guinness's Smiley but the resonance lives on.

The Night Manager, which continues this weekend, is a world away from that. No more cold war. This is an epic of complicated intrigue, violence and badness in modern times. The cast is stellar, the budget big. If a mini-series can feel like a maxi-series, this is it.

The producers wanted it to have the cinematic quality of a feature film, which indeed it has. Very few television dramas look like this. And how would you get that? By signing up an Oscar-winning director. Meet Susanne Bier, vivacious, engaging, amusing, Danish, Jewish, highly impressive maker of 15 films over the past 25 years, among them In A Better World, the Academy of Motion Pictures best foreign-language film of 2010.

It must be quite a thing winning an Oscar. "It's a big thing,'' she says. ''On the night, it's all so chaotic, so wild, so crazy and you have that golden statue in your hand. There's something solid about it. It gives you a certain confidence. When, like all other artists, I get into a black hole and I ask myself how will I actually solve the issue I'm dealing with, I can always remind myself I did it in the past so it will probably work out.

"Also, it generates confidence in the people I work with. I hope there's a certain feeling of trust, though trust is really always based on what you do on that particular day. It's not a free ride for whatever you do in the future but it's a solid indication of potential."

In A Better World is absolutely gripping not to say terrifying. Shot with close-up intensity, it is a story of terrifying violence and bleakness on two continents, a refugee camp in the Sudan desert - where a Danish doctor operates on patients savagely brutalised by a local warlord - and Denmark - where his son, desolated by his parents' broken marriage, teams up with a Swedish schoolmate desolated by the death of his mother. They get into the sort of trouble you'd expect there to be no coming back from. There is no cop-out happy ending but the film closes on a note of hope.

And that is generally true of her work. "I don't diminish the fact that tragedy happens to a lot of people but I think hope is just as real and just as intrinsic to who we are, and I do feel a responsibility as a film-maker not to leave my audience in a depressed frame of mind.

"Scandinavians can be thoroughly depressed. I've never been very good at being depressed. I come from an extremely happy and wonderful home. I'm very close to my parents. I speak to them every day and I'm very close to my two brothers who live in England." But it's a family that has felt the proximity of tragedy and the reality of threat.

"My father's family came to Denmark from Germany in 1933. They basically didn't want to live in Germany with the fascists in power and also they were seriously aware of how dangerous it would become. My mother was born in Denmark. They were still kids when their families left Denmark and escaped to Sweden. After the war, they came back to Denmark and met each other." Susanne grew up in the 6,000-strong Copenhagen Jewish community and went to Jewish primary school and later studied briefly in Israel, then in London before going to film school in Denmark.

"I've been brought up in an environment where we want to celebrate the joy of life. My parents experienced World War Two. We have a lot of fun, a lot of wonderful things but there's always the awareness that catastrophe could happen any time and, in my work, there's always that element of everything being turned upside down in a split second.

"And it's funny. My mother's always been incredibly positive. When I was a teenager, I had that teenager period when I only wanted to read sad poetry and listen to dark music. I wondered if my mother's positivity was because she was shallow. But it isn't shallow, it's for real and I've been able to infuse my movies with that."

Would she and the writer Anders Thomas Jensen, with whom she has worked for 15 years, ever do a film about the war her parents experienced? "We did do a script set around World War Two and its aftermath but somehow we haven't cracked it. We will do it. I'd be interested in making a movie about a Jewish subject if it's the right story. "

And that is what happened with The Night Manager. She was recommended to Simon Cornwell, son of John Le Carré, one of the series producers. He sent a first draft of writer David Farr's script for the first episode to Susanne Bier's agent who sent it to her with a whole bunch of others. "I saw the name Le Carré," says Bier, "I pulled it out, read it and just decided I really wanted to do it. I'd always been secretly envious of people who have had the opportunity to work with that sort of material.

"When I started making films, television wasn't very attractive. Now it's super-attractive. The Night Manager is so striking. It works on a thriller level but also on a more profound psychological level and getting the right balance has been quite a challenge. You go deep into the worlds of lots of characters. It's shot in the way you'd shoot a feature film. You don't shoot episode one, then episode two. In the morning you shoot the second scene from episode five, then in the afternoon you might be doing scene 18 from episode three.

And it's so big. It's six hours rather than an hour-and-a-half. It's like having three huge chessboards going at the same time and there's always an anxiety that you're making a mistake. What seems fantastic on a particular day may have repercussions further down the line and do you have enough overview to be sure you haven't made a fatal mistake. It's totally stimulating." More television? Having her work seen by many more people is a huge attraction. Her Danish films are seen extensively throughout the Nordic countries and some of them have gone international but, as she says, "they're always going to art-houses because they're in this weird, incomprehensible language."

Has The Night Manager gone smoothly? I ask. "Any kind of movie making is anything but smooth," she says "and it shouldn't be smooth. It's such a creative, explosive thing, so very exciting. You want to get away from it and have coffee with a friend without your phone ringing. Then when you're away for it you're dying to get back to it."

The crucial thing, as always, she says, is that the producers wanted to screen the film she wanted to make. That is the secret of happiness.

One comes from meeting her with the feeling that Le Carré is in good hands. And, more importantly for us and our Sunday evenings, so are we.