Comedy often makes fools of its critics, because it doesn't matter whether a film is good if it makes you laugh. Still, the cinema's no place for sketch shows; audiences require something to watch between jokes.

Arriving 12 years after BBC comedy The Office came to an end, Brent's first film outing is both very funny and very flawed. Despite the character having already outgrown his original milieu, it plonks him in the middle of another office, followed by another documentary crew, with diminishing returns.

Taking unpaid leave to pursue his dreams of rock stardom, Brent goes on tour with his band, Foregone Conclusion, and sidekick/rapper Dom (Doc Brown), who can't reconcile the unlikeliness of the pairing, especially when Brent is 'old, white and his music's terrible'. Make that brilliantly terrible. Though only performed in part, Brent's compositions are worth the admission price alone. Besides folky Lady Gypsy and funky Equality Street, there's an entire album's worth of skin-crawling ditties to savour.

Brent's monologues are equally good, but the film gets into trouble whenever he's not singing or oversharing. 'Maybe people don't find him funny but I do,' says Mandeep Dhillon's receptionist, just one of many underwritten supporting characters, although we never see her laugh. The documentary format is also repeatedly fluffed, and the comedy feels crueler than before. When Brent complains about an overweight ex-girlfriend it's funny because it reminds us what a hypocrite he is. Later, when we're asked to laugh at a larger lady eating, it suggests Ricky Gervais, who writes, directs and produces, feels the same.

After a brilliant opening salvo, and an amusing if seesawing middle, the film finally dissolves into cheap sentiment and crocodile tears. Brent considers himself a triple threat, excelling at 'music, comedy and wisdom'. Guess two out of three will have to do.

Wide release from Fri 19 Aug.