There's a beautiful scene in Nina Conti's show when Conti - a student of ventriloquism under the great Ken Campbell - appears as her own grandfather, himself a voice-throwing pro. Here, we meet him in his dotage, keeping loneliness at bay by ventriloquising his recently deceased wife back to life. In its cloth-capped, humdrum detail, it's a gem of a sequence - funny, poignant, and novel in its deployment of this cheesiest of music-hall crafts - stranded in the middle of a now-brilliant, now-infuriating hour of traditional, hand-up-a-puppet vaudeville.
The puppet in question is Monkey, and the conceit here is that the dummy and his mistress are battling for control of the show. Conti gives ventriloquism a thoroughgoing deconstruction, revelling in the artifice (Monkey: "I can't tell my arse from your elbow") without ever shattering the fabulous illusion. She also plays a series of guests on Monkey's Trisha-style chat-show - which would be a neat way for Conti to segue into some character comedy, if she didn't keep apologising for doing so. In fact, the show is at its most interesting when Conti finds new uses for her skills, as when she performs a one-woman Q&A with the audience, just by throwing her voice.
More frustrating is Conti's genital fixation (there's an awful sequence involving a giant talking penis) and her reliance for laughs on Monkey's potty mouth. ("What am I? Some kind of hairy Tourette's syndrome?") With such abundant ability as both actor and ventriloquist, Conti has no need for self-deprecation or cheap smut. The grandad vignette shows the way forward for Conti's distinctive talent in its marriage of the most bizarrely compelling of light-entertainment skills with an Alan Bennett-style monologue of homespun geriatric heartbreak. Ventriloquism hasn't been this tender since Orville's Song topped the charts. The knob gags are a needless distraction.
· Until August 27. Box office: 0131-556 6550
