Twice UK female beatboxing champion (2012 and 13), Grace Savage is at the top of her game at a young age (25). As she tells us, she's also an actress, but beatboxing is her main source of income - something very impressive for a practitioner of such a niche art.

If you know nothing about beatboxing before you see this show, this is a very good brief introduction. (If you know something about it, as many of the young audience seemed to tonight, it's a pretty impressive gig.) Beatboxing is mouth percussion; specifically, URBAN mouth percussion. Whilst mouth percussion is as old as the hills (think of Indian bol - the sounds of tabla playing mnemonics - or Scottish mouth music), its more obvious roots might be in 20th century jazz scat singing, where singers freestyle with sounds derived from instruments. Beatboxing began for real, however, with a palette of sounds derived from an electronic instrument - the portable beatbox - rapped over by hip hop artists from the 1980s on (if you're of a certain age, you might recall a certain Bobby McFerrin and his chocolatey vocal and beatbox skills back in 1988). Too poor to afford a beatbox? Then imitate it. Easier said than done; today's standard battle beatboxer will, as Savage does, have a full array of heavy nightclub sounds in their vocal armoury. Top flight performers such as Beardyman can, with loop stations, samplers and live mixing software, perform a full-length club set, no problem (and with no discernible difference from the real thing).

The icing on the cake though is that performers such as Savage, Beardyman and Shlomo (with whom Grace has worked, in his Vocal Orchestra) are also extremely competent singers and musicians - bringing the added layers and levels of melodic and harmonic complexity that make them stand out from the rest. And if you're lucky and the context is right, you might get to hear the really fun bits too: the bits demonstrating that a good beatboxer is more or less a human parrot, as happy imitating a toaster of a cab driver as they are an air horn or the sound of vinyl scratching.

Stand-out moments in the show are a powerful scene where the audience is blindfolded (though we could have done with a bit more follow-up tying this in to the show's narrative); Savage's spitting angry mysogynist rap lyrics over a projected background of increasingly filthy comments on her YouTube channel (including a hilarious one claiming girls can't beatbox since there's no bass - which Grace drowns out with the meatiest bass you'll hear without your head on a speaker); and the scene depicting her first ever beatbox 'battle' (public competition).

The show is structured as a tale of an awkward, musical girl growing up and trying to build her character, absorbing everything around her and regurgitating it to see what worked - with beatboxing as the result. It could have benefitted from a bit more meat on the bones to flesh out the story: more personal detail (were her folks musical?), more about EXACTLY how she made the transition from bedroom songwriter/guitarist to UK beatbox champion (there is a LOT of fierce competition for the title, mostly in London rather than her home county of Devon), more about what it's really like being a female in a world dominated - surprise, surprise - by boys. I personally could have watched another hour of this show with all that in it - and a lot more of her excellent beatboxing too. There was a lot of chair-based dancing going on in the audience and a happy babbling rabble - including a queue for cds - in the foyer afterwards. I bought her CD without thinking twice about it. If you get the chance to see her live, grab it with both hands.