For the past ten years, the British have shopped till they dropped. Now recession is threatening the nation's favourite pastime, and one of its biggest industries. It is the latest blow for many of Britain's beleaguered high streets. Retail guru Mary Portas wants to discover why boom towns are becoming bust towns, and what can be done to stop the extraordinary number of shop closures around Britain. Can anything be done to keep tills ringing and high streets alive? Mary takes on her biggest challenge to date: saving not just a single shop but the entire town centre of Tewkesbury, which is fighting the recession with true Blitz spirit.