Directed by Christopher Guest, starring Christopher Guest, Michael McKean, Fred Willard, Catherine O'Hara, Eugene Levy, Bob Balaban, Parker Posey, Ed Begley Jr, Jim Piddock, Jennifer Coolidge and Larry Miller.

There is a part of film history that will be forever 'Tap. With 'Smell The Glove', amps that go up to eleven and 18" high models of Stonehenge, Christopher Guest, aka Spinal Tap's Nigel Tufnel, carved out a place for himself in the minds of film - and music - lovers forever. Conceived and written by Guest, the much-loved satire about a heavy metal band on the way down was the first of his faux-documentaries. Since then he has turned his sights on amateur drama ('Waiting for Guffman') and dog fanciers ('Best in Show') but now he's back to the music in 'A Mighty Wind', poking (very) gentle fun at the folk revival scene of the 1960s.

When famed folk music manager Irving Steinbloom dies, his tone-deaf but devoted son Jonathan (Balaban) decides to organise a reunion concert of his most famous acts: traditional troubadours The Folkmen (the band formerly known as Spinal Tap - Guest, McKean and Shearer still on bass); clap-happy evangelical neuftet The New Main Street Singers and Mitch & Mickey (co-writer Levy and O'Hara), a famous husband and wife duo who divorced in the Seventies and haven't spoken to each other in almost 30 years.

As Jonathan Steinbloom coaxes the musicians into getting involved, the first half of 'A Mighty Wind' documents the past with a mixture of old black and white club footage, LP covers (check out Mitch's post-break-up albums) and material from live TV spots, gathering momentum as it moves towards the concert. Most of the has-beens are eager to recover what they see as their rightful moment in the spotlight with the exception of Mitch who, after years spent doing origami in mental hospitals, is an emotionally unsteady and reluctant participant.

In the talking head interviews, Guest's ensemble troupe - many of whom have worked with him since 'Guffman' - improvise brilliantly, making ridiculous characters believable by playing them without a trace of self-awareness or irony. There's Laurie Bohner (Lynch) of The New Main Street Singers, a former porn actress and leading exponent of WINC - Witches In Nature's Colours; catheter-seller and model train lover Leonard Crabbe (Piddock) and scene stealing Fred Willard as obnoxious hyperactive manager Mike LaFontaine, a former comic with a range of stupid catch phrases including "Hey, wha' happened?". However, it's the story of Mitch and Mickey that's most engaging with Eugene Levy and Catherine O'Hara pitch perfect as the former sweethearts and their final performance of sentimental hit single 'A Kiss at the End of the Rainbow' is curiously moving.

'A Mighty Wind' is such an affectionate look at the earnest and easily mocked Sixties folk scene that it's scarcely parody at all. There are plenty of gentle chuckles and warm smiles but there are times when the pace lags, too much time is spent on peripheral characters and the belly laughs of 'This is Spinal Tap' are few. The music - all written and performed by the cast - is first class, too good to be mocked, and the concert audience won't be the only ones tapping their toes during the reunion show. Warm and intelligent, 'A Mighty Wind' won't leave you blowin' in the breeze.

Caroline Hennessy