Emma Rice: The director with sky-high ambitions

What a glamourous life I lead," laughs Emma Rice, Kneehigh's artistic director, looking around a room in a rehearsal studio in south London that has all the charm of an inner-city classroom.

Rice joined Kneehigh, one of the most consistently playful and irreverent theatre companies in Britain, in 1994; last year it celebrated its 30th birthday. The company started out performing in a ramshackle barn on the Cornish coast: these days, it sells out Broadway and tours to Australia. It used to be a byword for slightly crazy fringe anarchists with something of the moon about them, bashing tambourines in fields and disused mines, but in recent years Kneehigh has been commissioned by the RSC and has played the National's Olivier stage. Their website still describes them as a local theatre company – but with their most recent commission a collaboration with the French soundtrack legend Michel Legrand, it's hard not to think of Kneehigh as a company on the verge of conquering the world.

In fact Kneehigh, who specialise in fusing music, circus and old-fashioned storytelling skills to create renegade adaptations of fairytales and revisionist versions of the classics, have perhaps become too big for Kneehigh. Their new West End show, a stage version of Jacques Demy's 1964 candy-coloured musical film The Umbrellas of Cherbourg, isn't strictly a Kneehigh show at all. "I haven't used any Kneehigh core members in this piece because of the levels of musicality needed. Kneehigh won't be remotely upset to hear me say this, but we just don't have the skills."

Kneehigh's anarchic spirit is sure to be all over Rice's approach to The Umbrellas of Cherbourg, about a soldier who goes off to war in Algeria leaving behind a girl who marries someone else. Together with Kneehigh's two previous film adaptations, their provocatively free version of Powell and Pressburger's classic 1946 film A Matter of Life and Death and the hugely popular Brief Encounter (which was performed in a cinema, and which cleverly spliced film footage with live performance), it also forms an unintended cinematic triptych.

Under Rice, Kneehigh has clocked up a mighty CV of adaptations and original work, upending classics such as Tristan and Yseult and The Bacchae. Nights at the Circus, a seedy, dreamy take on Angela Carter's novel hit the Lyric Hammersmith in 2006, while 2003's The Red Shoes, a landmark Kneehigh production directed by Rice and one clearly very close to her heart ("it came out of the break up of my marriage") ends a tour of the UK and Australia at London's BAC this month. Often presented with a strong female perspective, and always deeply personal for Rice, Kneehigh's shows are always defiantly populist in spirit and thrillingly rule-breaking in attitude.

This subversive streak hasn't always pleased the critics. A Matter of Life and Death, which opened at the National in 2007, received what Rice calls ruefully a critical "drubbing". The reviews, which mainly took issue with Rice's defiantly non-purist approach, led the National's artistic director, Nicholas Hytner, to describe the show's mostly male detractors as "dead white men", an outburst that then led to a furious blogosphere debate about whether some critics remain too long in their jobs and whether gender informs critical response.

Adapting to the demands of bigger and more mainstream audiences while keeping hold of their Cornish folk roots has been, Rice admits, a problem. "There's always been talk that Kneehigh has got too big for Cornwall," she says. "Success has been a real challenge to us, particularly when you struggle for so many years on the fringe. There's a great simplicity about struggle. You know what you want and you are always trying to get it."

' The Umbrellas of Cherbourg', Gielgud Theatre, London W1 ( www.umbrellasofcherbourg.com) to 1 October; 'The Red Shoes', BAC, London SW11 ( www.bac.org.uk) to 9 April