Meryl Streep: The lady has turned

There is a sense of occasion that comes with meeting Meryl Streep. It isn't only that her performances have been among the most skilful in modern film-making. She has also displayed a mix of tenacity and self-awareness that has guaranteed her miraculous longevity; and that, in turn, has made her cinema's nearest equivalent to royalty.

In person, the 55-year-old actress can be prickly and playful, but hardly regal. She seems to have found a way to forestall the reverence with which she is regarded: she swears like a trouper, laughs like a hyena, punctures deftly any solemnity that leaks into the conversation, and generally makes you forget that she is Meryl Streep. Lounging on a hotel sofa, she is cheerfully mumsy in her twin-set, slacks and sandals, her hair pinned up, her dainty glasses slipping down her nose.

She plays Eleanor Shaw, a venomous US senator, in Jonathan Demme's remake of the 1962 thriller The Manchurian Candidate. The picture is populated largely by nervous, creepy or inconsequential men, and Streep cuts through them like the Grim Reaper's scythe; everyone wilts in her presence. "I never get parts like this!" she whoops. "I get to drive a locomotive right through the first half of the movie."

Nowhere is this grandstanding, or Streep's girlish delight at it, more evident than in the striking scene in which she rallies support for her son's political career in a room full of doubters. By the end of her three-page, fist-shaking monologue, she has charmed or intimidated every character on screen, not to mention every member of the audience. "That scene reminded me of those script meetings where writers pitch their ideas to the executives who are going to lay down millions of dollars. I've been to a few of those meetings, to back up a friend or something. They're fascinating. The adrenalin's running, the room is packed with supporters, then there are the suits, all stony-faced. It's like Hickey in The Iceman Cometh - about selling on every level."

She relaxes suddenly and reclines in her seat, realising that she has slipped into the kind of salesmanship she is discussing. "It's also about getting your own way. Everyone understands that - everyone who has a family and has sat round the table and tried to win the day." I think of how Streep must have presided over the four children she has with her husband, the sculptor Don Gummer. It's hard to imagine her ever losing an argument, though perhaps she becomes a shrinking violet once she has her slippers on and curlers in. Certainly on screen she has specialised in perseverance and persuasion, even when the role seemed a bad fit. She was too composed to convince as a recovering addict in Postcards From The Edge (1990), but her belief in herself was winning: in the end, you gave in to her.

Her role in The Manchurian Candidate is as much a commentary on the actress's own persona, with its intimations of control and coercion, as it is a character in its own right. She brushes away impatiently any mention of Margaret Thatcher, of whom this performance will carry potent echoes for British viewers, complaining that people are simply frightened of powerful women. "There's a level on which this film touches a deep-rooted terror of women." But she wants it both ways. In one of the speeches that she was entrusted to write for the film, she exploits the gender paranoia that she decries in real life. She muses on her self-penned dialogue with a smile. "'Where are all the fucking men?' Yes, I'm proud of that scene."

Maybe the role feels so appropriate for Streep because it's all about performance, as so many of her most complex parts have been. It makes you think of the flinty, unyielding mother played by Streep in the 1979 film Kramer vs Kramer. She was excellent, too, as the mousey housewife who entertains poignant yearnings in The Bridges of Madison County (1995), where once again she articulated the inner tensions of a woman conditioned to keep her opinions to herself. If someone of your acquaintance has spent the last 30 years in hiding, and wishes to discover what's so special about Meryl Streep, you could do worse than show them the scene in which she silently contemplates escape from her husband's side to be with her lover, who is sitting in traffic in the truck in front. There's no dialogue: she does it with darting eyes and restless lips. It's pure sorcery.

She has been casting that spell since her time studying drama at Yale, when her stage presence became widely remarked upon, through to her small but piercing early roles, which often proved vital to a film. Without her turn as Woody Allen's brittle ex-wife in Manhattan (1979), that picture's view of women would have been unforgivably whimsical; without the tender suffering she revealed in The Deer Hunter (1978), Michael Cimino's gung-ho tirade (also starring John Cazale, her late fiance) would have buckled under the weight of its own machismo. So ubiquitous was she during the 1980s that everyone took her for granted: maybe she did too. If there was a meaty role in that decade, chances are it was Streep's for the taking - the tormented Holocaust survivor in Sophie's Choice (1982), the power-plant whistleblower in Silkwood (1983), Karen Blixen in Out Of Africa (1985), the reviled "Dingo Baby" mother in A Cry In The Dark (1988).

She could scarcely step out of the house in the morning without receiving an Academy Award nomination; each of the aforementioned films counted toward her record-breaking tally of 13 mentions, with Sophie's Choice responsible for the second of her two wins (the first was for Kramer vs Kramer).

She laughs when I ask if she could ever get bored of all that approbation. "Bored? Uh, no," she scoffs. "In a long career where you've been standing in front of people for so long, it's more like complete astonishment that they're not sick of you. When I've been nominated, I've thought: 'Well, that means I've got at least another 16 to 18 months in the business, thank goodness.' I'm just grateful I can still surprise people. Because I get bored with actors just like everyone does. I bet you've said this phrase: 'If I see this actor in another movie I'm gonna kill myself.' Haven't you? I have. I'll say: 'I can't look at this guy anymore. Him? No. No thank you.' Then I stop dead." She spreads her fingers, commanding an eerie silence. "And I realise that someone, somewhere, is saying that about me.

"In a long career, the trick is to keep it kicking," she tells me, toying with the blonde bangs that have escaped their clips. Recent projects have put this vague advice into practice: she brought crackling sexual tension to the role of a bored mum shooting the rapids in The River Wild (1994), while her romance with a snaggle-toothed orchid poacher in Adaptation (2002) was as touching and sensual as it was unlikely. Add to these her recent multi-way role (playing a rabbi, the mother of an Aids victim, and Ethel Rosenberg) in her friend Mike Nichols' television version of Angels in America, alongside The Manchurian Candidate and a cameo in the forthcoming Lemony Snicket's A Series Of Unfortunate Events and you have a CV of versatility and eclecticism.

She thinks it's hilarious that I assumed there was a strategy behind these choices. "No!" she booms. "What determines the films I do is the quality of the scripts. Working with people I like. School holidays. Everyone thinks there's a strategy because we're all paranoid. We think: 'A-ha. Very clever.' Well, no, not really. With The River Wild, it was nothing deeper than the fact that we were living in LA when the chance came up to do a movie in Montana, by a river, in the open air, with Curtis Hanson. Did I want to? Yes! Was there anything else to do? No!"

The impression you get is that Streep is out to correct a widely-held misapprehension about herself - that she is all technique and no spontaneity. The critic Pauline Kael never missed an opportunity to accuse her of being an automaton. Kael decided in her review of Plenty (1985) that Streep "just isn't there... She's strictly at interpreter". And in Silkwood, she pointed to a moment when Streep bites a ham sandwich: "Streep imitates raunchiness meticulously... But she hasn't got the craving to take that bite." I wish that Kael were alive today to see the effortless fizz that Streep put into Adaptation and Angels in America. Or to hear that she has signed up to work with Robert Altman, that pioneer of footloose film-making.

"Journalists always say to me, 'Is there a through-line to the characters you play?' That kills me. If there is a through-line, then it's down to the culture, and what gets green-lit, and which roles are available. If you track that back to the people who make the decisions to make the movies, then maybe you'll find a trend. But it doesn't rest with me."

She favours those directors who share her easygoing approach. "Looseness is the key for me - or the illusion of looseness. Actors are just babies at playtime. I want to have fun. I want to get a really good scene down, go to lunch, come back and do another really good scene."

Before I can stop her, she is bombarding me with proof that she is not the regimented acting machine that she was once accused of being. So devoid is she of controlling tendencies that she doesn't even view dailies anymore. "I used to. Dailies were my reward at the end of the day. Now a Martini is reward enough. Maybe I'm just more confident. I used to have to check that my performance was OK - check that it was alive, that it breathed, that it was fully human." She is laughing at herself now. "And when they take the footage to the editing room, do you know what? I'm glad. I've been invited to editing before, but I just don't want to see myself that much. My attitude is more like: 'Someone clean this up, please, will you?' A year later, they show me the film, I've forgotten what it's about and, what do you know, they've created a performance out of what I did."

'The Manchurian Candidate' is out on 19 November. 'Lemony Snicket's A Series of Unfortunate Events' opens next month