British women buy more knickers than any other nation in Europe. According to a survey carried out last month at the Paris International Lingerie Salon trade show, we buy 10 pairs each a year, whereas the Italians and Spanish buy only five and the Germans seven. Maybe it's because we have the best, and most accessible, underwear shops. After all, 45 per cent of the female population in the UK own a pair of M&S knickers: they sell a million pairs a week.

Knickers is a word idiosyncratic to the British. Americans call them "panties", the Spanish "bragas" the French "culottes", and the Italians "mutande". M&S calls them briefs, minis, tangas, thongs, hi-legs, hip- huggers and a variety of other names that trip off the tongue like a tongue- twister.

Tomorrow could be the only time this year that we will have no control over our choice of knickers. For the knickers that make their way into drawers across the country on Valentine's Day will have been chosen for you, by your significant other.

As women, we know our bodies, we know what we like, what feels comfortable - and, most importantly, what fits. This is where men rarely get it right. On Valentine's Day, little boxes with tissue-wrapped delicacies will be opened, and inside there will be a scrap of lace, a slither of silk or a puff of chiffon - probably beautiful, but probably also two sizes too small - and probably in black, white, or, quelle horreur, red.

It doesn't have to be this way. The underwear market is full of delights just waiting to be discovered. Antoni & Alison, famous for their superb slogan T-shirts, have been into knickers for seven years and, says designer Alison Roberts, it took almost that long for them to perfect their design.

"I was always changing them a bit here and there, skimming on the cut, especially around the leg," she says. "We wanted them to fit every body shape, no matter what size. We were not thinking of Baywatch babes, but real women." That's why they make only one style - high-waisted and with a high lycra content to improve fit. Whether in a size 8 or a size 14, they are perfectly proportioned.

Jo Asquith is another woman who knows her knickers. She has more than 100 pairs - due in part to her job as PR for the lingerie emporium Agent Provocateur, but mostly because she loves them - and the saucier the better.

"I don't own a single pair of boring white or big knickers, and never will," she says. "I just like really sexy things."

Luckily, she has a man who knows her tastes exactly. So what is she expecting tomorrow? "I have already bought what I want: a pair of ouvert knickers from Agent Provocateur."

A new addition to the underwear world is the 24-year-old model Tamzin Greenhill, who has opened her first shop, Femme Fatale, at 64 Wimbledon High Street. The store is stocked full of continental brands that Tamzin had only ever found in Paris: now she has brought them to our doorstep. Her favourite brand is Malizia, but she would never let her boyfriend, Jay, from Jamiroquai, buy them for her. "He might be a musical genius, but he's got terrible taste in knickers - I definitely buy my own." Like a true femme fatale.

So if you're wondering what kind of knickers to get for your woman, look no further than her underwear drawer. And remember to check the size.