In the first Bridget Jones movie, the scene where our curvaceous heroine dithers between choosing lacy lingerie or humongous hold-it-all-in knickers for a Big Night Out brought a roar of delighted recognition from the sisterhood. Our shameful secret was out, and it was gloriously funny. But it also marked another step forward in the relationship between women and their scanties. Over the past 150 years, underwear has changed from being a set of purely functional garments to become a symbol of female empowerment and sexuality. Helen Murray finds out just what was going on underneath those skirts beginning with the corset which began its decline in the 1910s, right through 'wasp waists', 'no bra', 'power-dressing' and 'underwire' to today's 'have-it-all' world.