Banksy: you know the score. Anonymous Bristol born graffiti artist who has left his mark on walls and buildings all over the world. His distinctive stenciling style is often used to make political points or to satirise those in authority.
Although occasionally local councils clean off his 'vandalism', Banksy is generally adored by everybody who likes to think of themselves as a wee bit alternative. It's worth pointing out that he doesn't sell photos of any of his work or mount any selling exhibitions: he's a proper anti-capitalist hero for people who are too lazy to be proper activists.