Shopping: Why can't a woman dress more like a man?

If strappy party frocks are not for you, knock 'em dead in a classic alternative, says

Style Police doesn't want President Blair's official Christmas card. We want stiffies - yes, stiff white party invites. By now your postman's sack is doubtless bursting. But have you had time to shop? Have you buffalo. Mary would have found it easier to book a double room in Bethlehem 2,000 years ago than bag the best high-street party frock this season. Know why? Because there is no way you can get by with one knockout frock and "clever" accessories. Unless your accessories are clever enough to do a smash and grab on Harvey Nichols come Christmas Eve, one dress is not going to cut it.

The fashion mags ran out of their 101 party frock ideas in mid-November. Mind you, unless you wanted to look like Disco Barbie this Yuletide they didn't help much. Three of Style Police's worst nightmares haunt the party season: Spandex, velour and glitter. Now we're not averse to a smattering of bugle beads and certainly wouldn't begrudge you the odd sequin. We don't call Christmas fashion's panto season for nothing.

So cleanse your minds of the sequin Blitzkreig and prepare for a masterclass in how to combine sex and chic in two divinely decadent pieces. When Yves Saint Laurent introduced the tuxedo jacket and cigarette-slim pant suit in 1966 he christened it Le Smoking. The Saint Laurent Smoking became synonymous with Seventies icons Bianca Jagger and Catherine Deneuve. It echoed androgynous, predatory Marlene Dietrich wearing white tie in Morocco. Monsieur Saint Laurent's fingerprints are all over the party season 2000.

December Harper's Bazaar devotes eight pages to Kate Moss modelling "New Year's Yves" blacks by Prada, Gucci and Cerruti Arte. But nobody does Le Smoking better than Saint Laurent. The original Smoking has never been bettered and current YSL Rive Gauche designer Alber Elbaz has followed the master's blueprint to the stitch this season. There is nothing sexier than bare flesh next to an elegant black satin lapel. Nothing streamlines a leg like a slim pair of black pants with a razor-sharp crease from waistband to ankle.

Isn't tailoring supposed to be demode this season? Le Smoking - like black, diamonds and crimson lips - is eternal. Think about it. The tux jacket reveals your best assets: a swan-like neck and a smooth decolletage. The pants stop at ankle length and allow you to wear wicked heels. You don't want to look Eighties? Well look at the ads for Gaultier's Fragile, Givenchy's Rouge Noir and Jitrois. Red lips, slick hair and Le Smoking equals queen of the night.

How to wear it

Style Police is going to do a Delia and serve you a menu for making Le Smoking party on. Wear it once for a swish dinner party with zero detail: no jewels but discreet diamond studs, nothing round the neck and basic black stiletto pumps. For hotel lobby cocktails with party people buy a diamond-encrusted or bugle-beaded camisole (no sequins). Accessorise with a sliver bag and the season's stiletto knee-boots.

For a family soiree slip a sheer black chiffon blouse under the tux, find a pair of flat beaded slippers and lose the jacket on arrival. Or twin the cigarette pants with a black leather, zip crop jacket and black beaded slippers. For Christmas Eve cocktails drop the pants and twin the tux jacket with the great clinging maxi skirt in Whitney Houston-esque leather or liquid satin but never, ever black velvet. If you're going to do the scarf thing, think Isadora Duncan black chiffon draping down your back and not the pastel pashmina.

For New Year's Eve you have permission to shimmer, baby, because you're the star. Wear Le Smoking but with a wicked five-tier diamante choker, a fat diamante bracelet and tear-drop diamond earrings. Take only an evening purse and make sure the stillies fit your feet like a second skin. Vamp it up and burn the dance floor.

Where to buy it

Bear in mind Le Smoking is your only major eveningwear buy and the pounds 1,460 for a kosher Yves Saint Laurent Rive Gauche Le Smoking doesn't seem so achingly expensive. If you are extremely smart and industrious, Style Police advises you trawl the vintage stores for an original YSL Le Smoking or a man's Forties tux jacket. Men were much more petit in those days and you will find an impeccably tailored tux fits like hand in calfskin glove.

If this sounds like a desperate measure then you try finding an exquisite Smoking on the high street. December Elle features a lovely black Synonyme by Georges Rech viscose suit (pounds 460) but Le Smoking it ain't. M&S has had a fair crack at the frock-coat cut tux (pounds 125), but although bravura tailoring appears simple, it is actually an art. You can't do Le Smoking on the cheap.

However, you can buy a little piece of Saint Laurent like this season's seminal black chiffon blouse (pounds 530) or extravagant black tailored pants (pounds 310). Warehouse has produced the fantastic silver chain-mail top (pounds 30) which is heaven under a tux jacket. Ditto Monsoon's bugle beaded sheer silver chiffon shell (pounds 80). If you do invest in a YSL Le Smoking you can probably wear it for the next millennium.

Address book

Marks & Spencer (tel: 0171 935 4422).

Monsoon (tel: 0171 313 3000).

Synonyme by Georges Rech (tel: 0171 235 3343).

Warehouse (tel: 0800 915

9902).

Yves Saint Laurent Rive Gauche (tel: 0171 493 1800).