Good improv comedy always requires a careful balancing act - an audience which is too rowdy or too quiet, a nervous cast member or an upstaging performer can drastically affect the performance. By adding music to the mix, Showstopper! runs even more of a risk; in the wrong hands this set-up could be a complete disaster. Fortunately, the cast, musicians and technical crew deliver a clever and impressive show which is a joy to watch.

The biggest audience laughs come from songs where the performers are restricted by audience suggestion and the on-stage direction of Dylan Emery; they shine when given scenarios, characters or artists to interpret. However, the troupe keeps control of the show throughout, maintaining plot continuity, character and musical harmony - very ably assisted in doing so by an on-stage band directed by Duncan Walsh-Atkins. It's clear that they take the principles of improv, and the musical quality of the show, very seriously - and the performance is all the better for it.

A show about musicals is always at risk of a few cheesy moments, and Showstopper!'s opening gambit - a staged phone conversation with the producer, "Cameron" - is heavy on exposition and comes across as slightly clumsy. However, the cast manage to keep West End in-jokes to a minimum, and as the performance gathers steam it goes from strength to strength.

The cast of Showstopper! have managed to craft a slick, confident comedy show well worth seeing. Of course, the performance will be different every night - but with this kind of talent, it's a safe bet for a great night out.

- Colleen Patterson