One cannot fault Mark Watson's work ethic. As well as his daily Fringe show, he is also writing a novel based on audience suggestions.

And at midnight last night he broke the record for the longest-ever continuous gig, clocking up an incredible 36 hours on stage.

It would be a shame if this amazing feat overshadowed his proper day job, because I'm Worried That I'm Starting To Hate Almost Everyone In The World is the kind of set that more experienced performers should aspire to.

Watson combines instinctive, crafted jokes with the most endearingly geeky personality in comedy.

The breathless show is inspired by the fact that a 13-year-old recently mugged him: "It's nice to see young talent coming through, the Theo Walcott of crime."

Afterwards life got to Watson and he whisks through his whinges helped by props plucked from a sack by audience members.

This is a simple. effective format. There are digs at Waitrose, Mick Hucknall and rude T-shirts, but his constant smile helps him avoid Grumpy Old Man territory.

This critic only has one gripe - why the fake Welsh lilt? Watson says it makes him funnier, but he'd be a winner with any accent.

• Until 28 August. Information: 0131 556 6550