Idiot Of Ants - Pleasance Beside, 6.20pm There are probably plenty of groups of four blokes out there who think they're hilarious, but sketch troupe Idiot Of Ants - Benjamin Wilson, James Wrighton, Elliott Tiney and Andrew Spiers - are almost certainly funnier.

A deadpan Wally of Where's Wally fame reading aloud from his book, four newly-born babies on a hospital ward and the two unprofessional plastic surgeons are all fantastically funny and show more invention and excellent acting than you could shake a Mitchell and Webb DVD at.

Another big hitter is the tenderly sung ode to an audience member that mushrooms into, well, a gang bang, and best of all is a two-part sketch about a stand-up comic who is haunted by three cockney ghosts. The pay off for this one is absolute comedy gold and will take some beating this festival.

The idea can be funnier than the actual material - see Wally and the (literal) clowns who turn their hand to painting and decorating - but any potential predictability is usually met with a smart twist. And as ever with sketch comedy the hit rate isn't 100 per cent (I would lose the the skit spoken entirely in love song titles and a hypnotist one), but the Idiot Of Ants still turn in a very high per cent. Say, 86.

More straightforward than the Fast Show, Idiot Of Ants is perhaps closer to Big Train (and often as good) in its realism/surrealism and how thoroughly thought through each sketch is. The foursome have a show on E4 this month, I hope that tricky transition from stage to screen leaves their undoubted talent in tact.

Four stars