David Baddiel tries to understand how the fashion industry works: what makes things fashionable? David is challenged by a listener from Wigan to explain why, when he needed to attend a family party a few years ago, the only trousers available to buy then were pleated. This sets David off on an unlikely quest to Paris Fashion Week to find the answer. When he arrives, he finds himself on the front row of a fashion show, bumps into fashion designers in the street, and is taken under the wing of one of fashion's most influential bloggers. But what is the answer, and can he explain it? Producer: Giles Edwards