Dir: Peter Hewitt. UK-Germany. 2002. 84mins.

The big selling point of Thunderpants for its target audience will also be the main deterrent for their chaperones: the idea of a nondescript, none-too-bright 10-year-old boy with a single extraordinary talent for farting. Our hero's peer group will, of course, love this premise. But, once dragged along for the ride, reluctant adults will also find unexpected pleasures in Pete Hewitt's slight, but irresistibly charming comedy. Released in the UK on 24 May (with the cheeky cod Star Wars copyline "May the farts be with you"), the film is likely to carve a modest theatrical profile and its whimsical, distinctively British humour may puzzle audience in certain territories. But Americans should enjoy its NASA sequences, with their gentle parody of such films as Apollo 13 and The Right Stuff, and Thunderpants' old-fashioned quality could prove its trump card in the longer term. Not anchored to a passing gimmick or fashion, its very timelessness should secure it a fragrant, lingering career in ancillary markets.

A pudgy boy with a pudding basin haircut, Patrick Smash was born with two stomachs, leaving him plagued by uncontrollable flatulence. Bullied by his schoolmates, he has just one friend, Alan A Allen. An eccentric boy genius with no sense of smell, Alan designs the film's eponymous thunderpants, a garment redolent of Wallace & Gromit's wrong trousers, which helps contain Patrick's emissions.

It turns out that the farts have, after all, certain uses. The world's second best opera singer (Simon Callow) realises their ability to simulate the high C which his own voice is unable to reach. Meanwhile, Alan succeeds in harnessing them as a potent energy source, and together he and Patrick win a competition to create a man-powered flying machine. NASA gets wind (as it were) of the invention and recruits the youngsters for the American space programme, which turns out to be run entirely by a team of child boffins. Called upon to rescue an imperilled space mission, Patrick's cherished dream of becoming an astronaut looks set to come true.

Like Bill and Ted in Hewitt's 1991 debut film, Bill And Ted's Bogus Journey, Patrick is one of life's cheerful underachievers who has greatness thrust upon him. Beneath its surface vulgarity, Thunderpants conveys the entirely inoffensive messages that everyone has something, however humble, which makes them unique, and that, with ingenuity and determination, handicaps can be transformed into assets.

A little more work on the script - by first-time writer Phil Hughes - might have refined this slightly banal homily and made the film less dependent on farting jokes. In other respects, though, Thunderpants is a very handsome package, with two very game central performances and a classy supporting cast. Callow, Stephen Fry, Paul Giamatti and Celia Imrie all clearly have fun with their characters, but Ned Beatty stands out as a jovial, Bible-bashing space chief.

Newcomer Bruce Cook is appealingly ingenuous as Patrick, while Rupert Grint, better known as Harry Potter's ginger-haired sidekick Ron Weasley, copes heroically with a set of false teeth and some tongue-twisting dialogue to create an amusing junior riff on the stock type of the nutty professor.

Chris Roope and Ann Maskey's surreal set and costume designs are one of Thunderpants' outstanding assets. Set in the same stylised late 1950s time warp as Hewitt's version of The Borrowers (alluded to in one of this film's many throwaway gags), it begins in a fusty Britain dominated by emerald green, down to the row of identical Mini Coopers parked in Patrick's street, which gradually yields to brighter, airier whites, yellows and greys after the action moves to America. All other technical credits are extremely polished and should enhance the film's adult appeal.

Prod co: Mission Pictures
Co prods: Pathe, Sky, CP Medien
UK dist/int'l sales: Pathe
Int'l sales: Pathe
Exec prods: Francois Ivernel, Cameron McCracken, Andrew Hauptman
Prods: Graham Broadbent, Damian Jones, Hewitt
Scr: Phil Hughes, based on a story by Hewitt
Cinematography: Andy Collins
Prod des: Chris Roope
Ed: Michael Parker
Music: Rupert Gregson-Williams
Main cast: Bruce Cook, Rupert Grint, Simon Callow, Stephen Fry, Celia Imrie, Ned Beatty