In Britain, she is something of a national treasure: beautiful, elegant, sophisticated and unafraid of roles that are none of those things. She has had a long and high-profile theater career that has included star turns in “Les Liaisons Dangereuses,” “Cat on a Hot Tin Roof” and “Private Lives,” as well as extended collaborations with Harold Pinter and Stephen Poliakoff. She has worked consistently in film and television since 1983, including as Lady Bertram and Mrs. Price in “Mansfield Park”; Margaret Thatcher in the BBC’s “Margaret”; Servilia, lover of Julius Caesar in HBO’s “Rome”; and Lady Smallwood in a recent “Sherlock.”
Jim Broadbent and Ms. Duncan in "Le Week-End." Credit Nicola Dove/Music Box Films

But Ms. Duncan, 63, has never broken through to the kind of international fame achieved by her fellow Britons Maggie Smith or Judi Dench, as critics here still regularly note.

“Anyone who has seen ‘Le Weekend’ — a compelling film about the complexities of mature love that is swiftly becoming a word-of-mouth hit — will be wondering why they haven’t paid nearly enough attention to the co-star, Lindsay Duncan, until now,” Daphne Lockyer wrote in The Telegraph after the film’s British release last year.

But fame, Ms. Duncan said over some warming tea, has never been her objective.

“There is a received opinion that there is a hierarchy of success, and that film is at the top,” Ms. Duncan said in her distinctive, immaculately enunciated tones. “But that’s not my hierarchy. I would rather give up acting than become world famous, because I think you pay a very high price. Writing and putting new plays out into the world has informed what I do, and I’ve had a lot more freedom to play really interesting parts.”

Meg, the 60-ish teacher of “Le Week-End,” is high on her list of great roles, Ms. Duncan said. Written by Hanif Kureishi and directed by Roger Michell, the film offers a portrait of a marriage at a pivotal moment, as Meg and her husband, Nick (Jim Broadbent), a university lecturer, go to Paris for a nostalgic weekend 30 years after spending their honeymoon there. Despite the rom-com allure of the format, the film is not exactly a rose-hued bundle of laughs.

“As you work on a script, you start in your mind to cast different actors, and the only one who consistently got through was Lindsay,” Mr. Michell said in a telephone interview. “Partly because she is a consummate actress, partly because she is also beautiful and sexy, very alive and wants more out of life. I couldn’t see many actresses who could convey that while also being someone who a glam French intellectual could pick up at a party.”

Mr. Michell, who said he tried to shoot the film in the spirit of the nouvelle vague, with natural light and real locations, added that Ms. Duncan had been enthusiastic about working this way.

“Lots of the scenes were shot in the street, with real people around them, not actors,” he said. “We had no trailers, no paraphernalia. I think you feel this in the film, like you are eavesdropping on them.”

It was rare, Ms. Duncan said, to come across a character as complex as Meg in film.

“She is walking away as fast as she can, she wants to be a person in the world, claiming her life, and if he isn’t up for that, it’s a problem,” she said, referring to Mr. Broadbent’s character. “And she is a sexualized character, which is crucial. Men play sexually active roles until they drop, but women aren’t generally allowed to.”

Mr. Broadbent, who had already played Ms. Duncan’s husband in the 2006 television movie “Longford,” said by phone that she “is impeccable and always surprising and exactly right.”

From the start, her approach seems to have been an instinctive one. Born in Edinburgh to working-class Scottish parents who then moved to Birmingham, Ms. Duncan began to act in school plays and to “creep into the neighboring boys school” to take part in their productions.

“I was just drawn to it, I don’t have any analysis of why,” she said. “I had no sense, as everybody in the world seems to now, that you could act as a profession. It was a friend who told me about drama schools.”

Ms. Duncan applied to several of them while working, among other jobs, as a bus driver and a barmaid. After “two or three goes,” she said, she was accepted at the Central School of Speech and Drama in London. “They weren’t begging me to come,” she added dryly.

After graduation, she spent a summer season in a regional repertory company. “It was a time warp,” she said. “The fringe was exploding in London, and we were doing ‘French Without Tears’ and Agatha Christie.”

But she soon found herself working alongside Albert Finney and Patricia Routledge at the Royal Exchange Theater in Manchester.

Job offers started to come from London, notably the invitation to join the Royal Shakespeare Company and play Marquise de Merteuil opposite Alan Rickman’s Vicomte de Valmont in Christopher Hampton’s new “Liaisons Dangereuses” in 1985. Ms. Duncan was initially reluctant to commit to the full-time touring schedule. (It was about that time when she met Hilton McRae, to whom she’s married; they have a grown son.) “But I knew it was extraordinary,” she said. “The play came off the press a classic.”

Ms. Duncan’s icily seductive performance won her an Olivier award and a Tony nomination, but when the play was made into a Hollywood movie, the role went to Glenn Close. Asked if her life might have taken a different turn had that decision been different, Ms. Duncan shrugged.

“I was so lucky to create that role in a wonderful production when everyone was at their best,” she said. “You always remember the delicacy of the work you do on a new play — the delicacy and the rigor and the courage. It’s easier to find that in the theater, although ‘Le Weekend’ is absolutely up there.”

Asked why he thought Ms. Duncan hadn’t achieved greater fame, Mr. Michell paused. “Perhaps because we luxuriate in this country in this abundance of acting talent,” he said. “Lindsay is deserving of great fame and fortune, and I’d love it if she got that.”

Ms. Duncan didn’t sound so sure.

“I want to have the career that is my choice — what interests me, what doesn’t,” she said. “I feel more and more strongly about that.”