Ah-Fang, an illegal Chinese migrant, works as a housekeeper in an 'Oriental' brothel in Cheam. She earns £180 a week - a step up from the £50 she got picking leeks. And at least she doesn't suffer the degradations of the brothel's 'Misses' who sell sex for 14 hours a day. In the first of two extracts from her new book, Hsiao-Hung Pai hears what life is like for the 3,000 Chinese women who work in Britain's sex industry