The Devil Wears Prada (PG) <!-- none onestar twostar threestar fourstar fivestar -->

Claws out, dressed to kill

In The Devil Wears Prada, skinny young women sprint around the corridors of the New York fashion magazine Runway with the breathless panic of extras being pursued by a monster in a B-movie. When their boss Miranda Priestly (Meryl Streep) enters the office we find out why they look so exercised: she is a monster, half-woman, half-winged fury, and the most terrifying thing in heels since Rosa Klebb.

Miranda never raises her voice when she exerts her cold command (she speaks only in the imperative mood) and fixes a look of gimlet-eyed disdain on those who can't instantly fulfil her requirements. She never says "hello" or "thank you" or anything else that might be construed as a mark of courtesy. Editor is her official job-title, but tyrant queen is essentially her calling.

Movies need monsters, and Streep may just have given us a classic here. What's so striking is that the icy blasts of hauteur she turns on her staff have a physical as well as verbal comedy. The screenwriter Aline Brosh McKenna has supplied her with some withering putdowns - "Please bore someone else with your questions"; "The details of your incompetence do not interest me"; "Yes, move at a glacial pace. You know how that thrills me" - yet Streep brilliantly uses a purse of her lips or the tilt of her chin to communicate with her minions, ie the rest of the world.

When she first receives Andy Sachs (Anne Hathaway), the latest unfortunate to apply for the job as her junior assistant, just a flicker of her eyes is enough to show how completely and profoundly unimpressed she is by this coltish young wannabe. It's a look I well remember from the repertoire of a frightening ex-girlfriend.

The job of chief assistant belongs to Emily, played, in the movie's other outstanding turn, by the young British actor Emily Blunt. This pert miss has prostrated herself before the sovereignty of Miranda for so long she ought to have carpet burns and, having learnt the tactics of humiliation from the best, now wields her own little tyranny over Andy, shrieking the coffee order and errands down the phone as if they were co-ordinates in a battle plan.

If she is the Ugly (though actually rather beautiful) Sister to Miranda's Wicked Stepmother, then Andy is Cinderella, drudging through every menial task and scorned for her blue sweater, clumpy shoes and sensible skirt - "Are you wearing that for some hideous skirt convention?" enquires Emily.

Fortunately, Cinderella has her Buttons, too, in the form of fashion director Nigel (Stanley Tucci), who instructs Andy in the rudiments of survival at Runway: instead of moaning about Miranda she will have to, in that repulsive phrase, dress for success. "You're in desperate need of Chanel," he tells her, cueing the Pretty Woman-style montage in which we see Andy enter the magazine's vast samples wardrobe and pupate into a high-fashion butterfly whose brilliant markings will ensure that no one looks askance at her again.

This fairy-tale interlude is the closest it gets to its source, a chick-lit novel by Lauren Weisberger, who served a similar apprenticeship to Andy's under the editor of American Vogue, Anna "Nuclear" Wintour. But the director David Frankel, sometime alumnus of Sex and the City, doesn't let the movie swoon too long; he stitches this gossamer stuff together very neatly and knows when to move it along.

For the film is actually teeing up a moral. Andy, a graduate high-flyer with ambitions to be a serious journalist, begins the story mocking the fripperies and folderol of the couture business: what else could a thinking person do with it? She's been told that her job "opens a lot of doors" without really caring what the doors open to.

After a few months, however, she is neglecting her nice chef boyfriend (Adrian Grenier, from television's Entourage) and blowing out her mates at short notice because Runway has got under her skin. Will Andy trade in her soul right along with her drab duds? That the question should concern us seems remarkable, as the toes she must tread on while shinnying up the career ladder belong to despots-in-waiting, junior Mirandas - but the doe-eyed innocence of Hathaway perhaps makes us want to believe that not every bright young woman would be seduced by the prospect of free shoes and handbags for life.

There is a scene, late on, when I feared that Miranda's regal poise was about to collapse, taking the whole movie along with it. In Paris for fashion week, Andy stumbles on Miranda, up late in her hotel suite, her face denuded of make-up and contemplating some bad news from home.

It seems unlikely, from all we know of her, that she would ever be so caught off guard, but just as we think she's about to break down in tears she recovers herself and segues straight into a discussion of placements for the next day's gala lunch. Streep handles this minute slip of the mask with the same aplomb she does everything else, and there is something heartless, and quite majestic, about her response to Andy's solicitude. "Is there anything I can do?" she asks the boss. "Yes - your job." Ouch!

The list of great movies about the fashion business is not long, and it does not include either Pret à Porter or Zoolander. Maybe The Devil Wears Prada wouldn't make it either, but it doesn't need to; it's something better, a great office comedy.

Like so much modern satire, it defers to what it allegedly derides, and makes icons of the people whose clay feet it is busy exposing. Yet you would have to be awfully high-minded not to enjoy the film. Hats off to Frankel and Alina Brosh McKenna for making the kind of movie that's hard to find any more, one as snappy and juicy as fresh bubblegum.