Richard Herring's shows are consistently among the most accomplished on the Fringe and Hitler Moustache (Underbelly) was the subject of some controversy before it even opened. Attempting to reclaim the sinister toothbrush moustache for comedy - it was, after all, Charlie Chaplin's first - Herring leads his audience on a superbly constructed and wickedly clever journey through their own liberal prejudices. What makes a racist, he asks, in a convoluted dialogue with himself, and who decides when comedy is ironically offensive as a challenge and when it is just plain offensive? Beneath the high-octane set pieces, however, is a serious point that Herring clearly feels strongly about: those who didn't bother to vote have done as much damage as those who voted BNP (the party, not the bank).