Lindsay Duncan: When in Rome...

She's played them all: from the icy Marquise in 'Les Liaisons Dangereuses' to droid TC-14 in 'Star Wars'. And here she comes as Julius Caesar's lover in the epic new BBC drama 'Rome'. So why, asks Kevin Jackson, do we not speak of Lindsay Duncan in the same breath as the Dames, Judi and Maggie?

Word from deep inside the camp of Rome, the whoppingly expensive 12-part co-production between HBO and BBC Drama, is that the series was at one time pitched to the money guys as an irresistible blend of two contrasting house styles: the grittiness, amoral sprezzatura and unflinching violence of The Sopranos, plus the conspicuous literacy, gravitas and high-megaton classiness of I, Claudius. (Indeed, further rumours have it that the project began its meandering, several-year route to the small screen with the idea for a fairly straight remake of the old BBC series.) This was always a dangerous brace of comparisons - what if they'd ended up with the street-wise grittiness of I, Claudius and the high literacy of Tony Soprano? But, by and large, the televisual conspirators seem to have got away with it so far. Rome has legs.

True, there have been dissenting voices among the American reviewers, and internet postings suggest that stuffier viewers in the deep heartlands have been less than chuffed about the series' penchant for male nudity. None the less, plenty of newspaper critics have already handed out their five-star ratings, the audience figures for early episodes have been well up above the three million mark and one performance, at least, has been described as "outstanding": Lindsay Duncan's, in the role of Servilia of the Junii, mother of Brutus, lover of Julius Caesar.

This verdict was privately echoed by a British HBO producer I nobbled a few weeks ago ("She's terrific in it, really one of the show's great assets - and she doesn't put on any grand dame airs and graces, either, she's very no-nonsense, and she's become a good friend over the last year"). But it won't come as much of a revelation to anyone who has followed her unusually eclectic and high-definition career over the last couple of decades.

The crowded Duncan CV includes a great deal of stage work, both on home turf and on Broadway, most memorably an Olivier Award-winning and Tony-nominated performance as the predatory, proto-Nietzschean Marquise de Merteuil in the RSC's hit production of Les Liaisons Dangereuses (a shame, to put it mildly, that they gave the movie part to Glenn Close), and then a comparably sexy lead role a few years later in Cat on a Hot Tin Roof. There have been several top-notch collaborations with our latest Nobel Laureate, Mr Pinter - Celebration, The Room, Ashes to Ashes (and she also read the audio-book of Marie Antoinette by Pinter's wife, Lady Antonia Fraser); and she has punctuated these theatre assignments with all manner of interesting work on television, notably as characters written by Stephen Poliakoff (Marilyn Truman in Shooting the Past) and Alan Bleasdale (Barbara Douglas in GBH).

Her film career was properly launched in 1983 with a starring role in Richard Eyre's gentle comedy of sexual politics Loose Connections, in which she played a semi-posh feminist stuck in a long-distance car drive with an unreconstructed bloke's bloke (Stephen Rae) clumsily pretending to be in touch with his feminine side. Since then, to the bafflement and frustration of her more discerning fans, she has tended to play character parts rather than leads; there is glum comedy in the fact that by far the largest audience she has ever reached - in Star Wars - The Phantom Menace (1999) - was as the voice of a droid, TC-14. "I desperately wanted to play the part of Darth Vader's mother - I think she ended up being played by a Scandinavian actress - because my son was completely crazy about Star Wars. I think that every actress who had a young child craved that part - 'You don't know what this will mean to my son!!' ... Anyway, as a consolation prize I was given the voice part. I think I have two lines... something like 'My master awaits you.' Not a finely honed character, but then you get all this mad fan mail saying things like 'I was knocked out by your contribution to The Phantom Menace...'. Incidentally, my husband Hilton, years before I knew him, was a fighter pilot in one of the earlier films."

It's not just the Star Wars nutters who have been watching and listening to her carefully. Brighter critics kept noticing her appearances in a range of parts, from resentful writer's wife in Prick Up Your Ears (1987) to her bravura double role as a drugged-up aristocrat and her anxious sister in Mansfield Park (2000). Until the well-publicised debut of Rome a few weeks ago, she was probably most widely known in the US for her supporting role in fluffy piece of touristic escapism, Under the Tuscan Sun, which didn't make much of an impression here but has developed into something of a cult classic for wistful, educated Americans.

Quite a career: and there can't have been many people who might have predicted it on the strength of her very first television cameo in 1975; this - curious chance - was also set in Ancient Rome. Well, an ancient Roman town, of sorts: the smutty, single-entendre boobs-and-bums world of Frankie Howerd's Up Pompeii!

"I played a slave girl called Scrubba - S C R U B B A! It was for an Easter BBC special. A few months ago, when we did the Rome cast outing to Pompeii, the guide asked us if we had ever been there before, and the whole story came out, and caused such mirth. Frankie Howerd was a terrifying man, terrifying and brilliant. I remember going for this job at the BBC, and was asked to show my legs ... and I remember the photo-call. I was a bit bigger in the chest than I am now, more curvy, and people asked you to do incredibly tabloid stuff: 'Oi, Lindsay, lean forward a bit more daaahlin, caahm on, give us a big smile, cross yer arms...' I was in a fog of obedience, and when I got home I just burst into tears. I was very young."

While it would be unforgivably coarse to join those lensmen in a bout of prose slavering over her good looks, it would be prissy to shirk the obvious truths that most film actresses are still required to be beautiful. Some three decades and more after her stage debut, Lindsay Duncan is looking, well, terrific: movie-set glamorous even sitting inconspicuously in a north London coffee shop, dressed in regular old T-shirt and dark trousers with no fancy lighting set-ups, and no more than the most perfunctory hint of slap. Fine-boned and patrician in the face, slender in the body, she could easily pass for a good 15 or 20 years younger than her true age (She was born in 1950, and doesn't seem to give a hoot who knows it.)

Quivering heterosexual male reviewers from the time of Liaisons onwards have rhapsodised about her overpowering "Ice Queen" erotic force, and you can easily see what they mean - but, come on chaps, that's called "acting". In person she doesn't come the icicle-and-napalm act at all: as the man from HBO said, she's no-nonsense, clubbable, co-operative. And, like a great many actors, reluctant to be analytical about a talent that is in large measure intuitive - which is one reason why she sounds wholly convincing when she claims never to read her reviews any more, good or bad.

"Recently I made the mistake of opening a bundle of reviews that someone had sent me of a production from years and years ago, and someone had written a really lovely review except that it made a remark about the way I spoke: 'A lot of people find her voice terribly irritating.' Do they? I had no idea. So it's never safe. Better just to leave them to gather dust."

Not, one hastens to add, that she's had to suffer many bad reviews. Her low point in artistic terms was probably the BBC's adaptation of A Year in Provence: "Some people thought that it was going to be the end of my career. I remember my husband playing bridge with someone who said that I should sue the BBC, because it was such a disaster."

Was the whole thing an unmitigated mess?

"Well, it was fun to be in France. The scripts were... not quite what I had expected. I'd read some early drafts which were more ambiguous, and more in keeping with the original material. All right, he [Peter Mayle] has some comic set pieces, but there is something more serious there about trying to live out a dream, spin out a fantasy. I think the television series got itself into a bit of a corner - it tried too hard to be a sitcom, which didn't work, and wasn't the thing that had captured people's imaginations when they read the book. It was the first piece of work I took on after I'd had my baby, and it enabled me to work in two convenient blocks, one in the spring, one in the winter, in a beautiful place that I'd never been to before, and to bring my little son with me. I have quite a knack for turning a job into a rather delicious life experience - Rome was like that too, they rented me a lovely place near the Campo di Fiori."

Her voice is clear and emphatic, her accent is in the higher social registers of RP, and there isn't an audible hint of her Scottish ancestry or brief period of childhood residence in Birmingham: "My mother was always deeply attracted to anything medical, and I think she would have loved me to have been a doctor. My father was in the army for 21 years, came out just before I was born. There was no history of showbusiness on either side of the family, but they were completely supportive. Educationally, like a lot of Scots, they had very high standards, and they put a lot of effort into making sure that I was reasonably educated. But in terms of what I wanted to do - and without ever discussing it - I just had their permission to be what I am. Sadly, my father died before I even left school, let alone got into drama college."

Like many professional actors, she first caught the bug in school productions. "Across the drive from our all-girls school was the all-boys school, and my great friend Kevin Elyot, who's now a playwright, was a pupil there. They had a much freer approach to drama, and did contemporary writers, and somehow I sort of crossed the drive and got into the boys' school. And then when Kevin, and another friend called Michael Burlington, went on to Bristol University drama department - a very hot department at the time - I followed them, doing odd jobs in pubs and as a bus conductress, but mainly just hanging around in the drama department. I staged my own production of Joe Orton's Funeral Games, and had to take lunchtimes off from my pub job to do it. And after being turned down several times by the likes of Rada, I was eventually accepted by Central School [of Speech and Drama]. The doors weren't exactly flying open for me.

"It was little, little footsteps, I had no idea where they were leading. I was very naïve - it was partly the times. People nowadays are much more sophisticated - if they want to act, they're looking at a whole range of options, they may not even consider theatre at all, they'll be looking at television and thinking 'Ah, I could get a foot in the door there, this is what I'm selling.'"

And after graduation? Did you work immediately? "Yes - we went straight from three years of classical training to weekly rep: Agatha Christie, French Without Tears, all that stuff." Do you look back on that time with nostalgia? "Oh, I adored it. It was very healthy to go from head-banging over a bit of Chekhov ... into that rough and tumble, with the sense that we were doing something quite old-fashioned. Their was an air of seaside holiday about the whole thing. We were billeted in this boy's prep school, which was beyond weird, with iron bedsteads and bare floorboards, almost Dickensian. You'd learn your lines on the beach - you have loads of brain cells at that age that you can employ learning lines after being in the pub - and then transfer to the end of the pier at Cromer."

And how did you make the transition from the end of the pier to more mainstream theatre? "I suppose the first proper job was the opening season at the Royal Exchange ... Albert Finney and Eleanor Bron and Tom Courtenay, that triumvirate - this was a project they had all held dear for many years, trying to get this theatre built. We did The Rivals, The Prince of Homburg, The Skin of our Teeth, What the Butler Saw... Serious work, with very good people, in a stunning theatre with all the shared excitement of a dream coming true. It was the first time I ever got a sense of context for the work I was doing. Up to then, I'd never really thought seriously about whether I was doing the job properly, and whether I had anything more than that certain kind of charisma which most young actors have. To be more than that is a question of work and experience. So though it was frightening, it was the beginning of proper work."

Work which continues in a reassuringly steady fashion to this day. The second series of Rome is already in pre-production, and it may go on to three, four or even five seasons; she'll probably return as Servilia for as long as the writers want her, and the claims of ancient history permit. Since wrapping the first series, she's already completed another feature film, called Starter for Ten, and is hungry for more theatre productions (long-standing ambition, if she's called on by the right director: Schiller's Mary Stuart). "I felt very differently about this a few years ago, I thought I might just go off to France, sit around, garden. But now I have an enormous appetite for work again. I know I'll always work. In what form, it really doesn't matter. Now that my son's 14, he's getting to an age where he's more and more independent, I'll no longer have to feel responsible for him every hour, and that opens up all sorts of possibilities."

Just so. There's a very good chance, a wise friend recently suggested to me, that before too long she is going to be universally recognised as one of the great stage actresses of her generation, up there in the ranks occupied by the likes of, say, Dame Judi Dench. When I mentioned this prediction to the man from HBO, he disagreed. "Absolutely not," he said. "No, not Judi Dench. I reckon she'll be much more like a 21st-century Maggie Smith."

'Rome' begins on BBC2, 2 November