The Watch is a rather shonky, slapdash construction but as mainstream comedies go it works well enough. It mashes up elements of Old School, Ghostbusters and Body Snatchers in its story of four guys forming a Neighbourhood Watch, only to discover an alien invasion.

As is the way with modern American screen comedies, it is a little bit stupid and a little bit smart, sometime crude, sometime subtle, and there is a bit of novelty gore this time too.

It is set in the kind of mesmerisingly opulent American suburbia where everybody lives in mansions and there is an air of indulged affluence to the humour in which American comic superstars get to goof around in the sacred name of 'improv'.

People like Ben Stiller, Vince Vaughn and Jonah Hill are so secure in their comic personas (especially Vaughn whose comic performances post the Psycho remake have been so indistinguishable they could be panels of a Warhol silkscreen) that no director is going to ask them to stick to the script.

With improvisational comedy on screen, what you gain in spontaneity you lose in smugness. Whole scenes in The Watch look entirely improvised but the 'pleased with themselves' air actually works in the film's favour; it tallies with the film's vision of suburbia as a place filled with complacent, over-rewarded but unfulfilled boars running around trying to give a purpose to their consumerism.

It helps that the film sucks in some fresh blood in our very own Richard Ayoade. The film wisely allowed him to play his set comic persona (basically a slightly less extreme version of Moss from The IT Crowd) and puts him on equal footing with the other stars, which is rather flattering as this is a considerable step up for a man whose previous big screen appearance was a small role in Bunny and The Bull.

He's not only the best thing in this film but having someone fresh and original to bounce off lifts his co-stars to do a bit better than in recent films.

THE WATCH (15)

Director: Akiva Shaffer

Starring: Ben Stiller, Vince Vaughn, Jonah Hill, Richard Ayoade, Rosemarie Dewitt and Will Forte

Length: 102 mins

***