How Donald Mack is still labouring under the illusion that he is a comic defies rational explanation - you'd get pithier, wittier, more original observation from the average cabbie.

Yet every year he brings another show to the Fringe and 2009, unfortunately, is no exception. This time around, 'Big Mack' claims to be exploring the idea that he may be a black stereotype, mainly on the grounds that he likes KFC, smokes weed and went to prison (once, to visit someone). Needless to say, Chris Rock need not get twitchy - provocative racial commentary this ain't.

In between making crass comments to two girls sitting with their parents in the front row and quizzing everyone else on where they come from with a census officer's attention to detail (and indeed, famed sense of humour), Mack throws out a string of charmless, empty anecdotes.

One particularly knuckle-biting example; he was going through customs and officers searched him and he had smuggled hash in his pants but because he was black, they assumed the bulge was his enormous cock and he got away with it. Is this really meant to be material?

Still, at least it's a story of sorts; by the final part of the show he's jabbering away about farting on your girlfriend but being careful not to 'follow through'. The overall effect is offensive (and not in an edgy, desirable way), thoughtless and about as funny as cot death.