For more than three decades the ballet dancer Sylvie Guillem has performed as principal dancer at most leading ballet establishments, redrawing the boundaries of the genre. But at the end of this year she will be giving her last performance in a worldwide farewell tour. She will undoubtedly go down in ballet history as one of the greatest dancers of all time - but she's famously been dubbed 'Mademoiselle Non' for being too assertive. Hardtalk speaks to her about that, as well as the poisonous rivalries in the world of ballet and her activism to save the planet.