'Shangri La', 'the Rooftop of the World' - locked away in its Himalayan fortress, Tibet has long exercised a siren's hold on the imagination of the West. Tibetans are used to hardship, and despite the disastrous Chinese occupation, they have managed to keep their culture and humour alive. Travel in Tibet comes with some ludicrous permit requirements. The present Chinese policy on individual tourism in Tibet seems to be one of extorting as much cash as possible from foreigners, but not so much as to scare them off completely.