With the West End currently awash with mega-musicals, who has time for only one chorus line a night? You'd never get through them at that rate. Eric Rockwell and Joanne Bogart, writers of these delightful, scalpel-sharp 100 minutes of parody, have the answer. See five musicals! In one evening! With just one plot to follow!

The premise is simple: June can't pay her rent, her landlord is evil, her boyfriend useless and her best friend bursting with unworkable advice. The twist is inspired: June's travails are portrayed, in true Whose Line is it Anyway fashion, in the styles of various legends of musical theatre. Cue the lovable foibles of Rodgers and Hammerstein, Stephen Sondheim, Jerry Herman, Andrew Lloyd Webber and Kander and Ebb.

Those with only the sketchiest knowledge of this most send-uppable of genres will still find much to amuse. There's the paramour who declares "You make me want to sing a show tune", and the dying heroine who manages to rouse herself for one final, stirring solo.

But for aficionados, each extra piece of knowledge adds enjoyment and mirth. Where do Sondheim's angst-ridden, linguistically versatile protagonists live? A New York apartment complex called The Woods, of course.

Julian Woolford's energy-packed production fits perfectly on to this tiny stage, with its single accompanying piano. The spirited cast of four, uniformly excellent, have especial fun when Rockwell and Bogart keep their focus drum-tight.

The Lloyd Webber section, Aspects of Junita, founders for taking too many shows as its target. Kander and Ebb, on the other hand, find themselves in a cabaret in Chicago, where everyone deploys chairs in non-conventional ways and speaks in oddly inflected German accents. Like the man said: "Drink your wine/ 'Cos life's a Cabernet." A vintage one, at that.

• Until 28 January (020 7226 1916).