The description of Impropera as its operatic equivalent of Whose Line is it Anyway?, seems a decent fit - especially now that, post-Borat, the genial humour of that Channel 4 show seems just a little comforting and grown-up.
Impropera comprises a pianist, a clarinetist/saxophonist and four singers, who improvise musical numbers around ideas they have extracted from the audience. It helps that Niall Ashdown, the least refined of the singers but the show's natural compere, moonlights at the Comedy Store.
All six performers - who, in this tiny theatre, are practically in the audience's laps - have the requisite library of operatic or music-theatre styles down pat, and that's what makes this work, though a few killer one-liners would have jogged the pace along between numbers. Best of the stand-alone pseudo-arias in the first half was Morag McLaren's spot-on parody of a Russian diva lamenting the loss of the phone number of someone called Nigel.
The second half involved a mock one-act opera that ended up being called The Little Banker of Worthing. Pianist Anthony Ingle led the singers through at least a dozen musical styles, from Verdian rum-ti-tum - to which you can sing anything it would seem - and artfully ripped-off Wagner, through to Gershwin and the numbing bombast of Andrew Lloyd Webber.
The performers know exactly what level they are allowed to descend to: there's a duet about Shagging Lots of Ladies, yet the suggestion of sex aids as a topic for a encore is coyly turned down in favour of one about houseplants. Any real subversiveness is adroitly deflected, but it's all good clean fun.
· Until Saturday. Box office: 020 7287 2875.
