British designer Matthew Williamson has berated Britney Spears for her appalling dress sense, insisting he would never let the singer model his collection. The fashion guru, who boasts a huge celebrity clientele including actresses Keira Knightley and Sienna Miller, slams Spears' sense of style, and even questions her fame. He says, "I'm not paying anyone to wear my designs. "I wouldn't really like to say, but if one of Girls Aloud walked into my store it might not be to my liking - or Britney Spears. "The girls I dress have all got a similarity. There's obviously different levels of celebrity - the more A-list the better. "The kind of girls I dress are Sienna Miller, Jade Jagger, Helena Christensen, Keira Knightley. Girls who are beautiful inside and out, with fabulous careers. They're all doing great things."