The Polyphonic Spree, Shepherd's Bush Empire, London

Rejoice! It beats Peter and the Wolf

The Polyphonic Spree, a white-robed 26-piece Texan orchestral-choral pop band, have fittingly chosen a Sunday night to end their mission to save the pop souls of England. Tonight our Sunday evensong will be colour co-ordinated and air-punchingly uplifting.

The Polyphonic Spree aren't yet big news in America, but then children over there aren't ritually dragged to Andrew Lloyd Webber musicals from the tender age of 14 and mostly didn't endure Britpop's perkier conceptual pretenses. Anticipation is tangible, and this audience act like they positively created this band, bestowing tender parental attentiveness as the Spree take their first faltering steps into the adult world of the music industry.

The music, wildly upbeat orchestral pop that takes in Mercury Rev, Hair-era musicals and late-Sixties California, is wildly infectious. On record its simplicity of themes (reach for the sun, suicide is a shame, etc) can sound a bit naive. But seeing 26 people imploring the sun to shine down is something you just have to see at least once in life. The band have unwittingly formed a kind of young person's guide to the orchestra, probably something of a revelation for those whose only prior exposure to classical music has been William Orbit's take on Barber's Adagio for Strings or those naff string parts in trance records. I spotted a child of about six on his dad's shoulders, smiling and swaying. Lucky beggar. I had to sit through Peter and the Wolf at that age.

In an era when cool is the chief virtue and feigning indifference considered a life-skill, it's amazing to find a band who spur their audience to such open-mouthed glee and random acts of kindness. Quite unbidden several audience members excitedly offer their "where I discovered them" stories and offer me drinks. We're all grinning now, reverently wide-eyed and painless.

The pop life leaves its mark on most (just ask Jarvis from Pulp who joins the choral section at the back, resplendent in regulation white smock). But tonight Tim DeLaughter, his curly brown locks, all messianic carpenter chic, looks about half his 36 years. Choristers smile at each other, hands thrown heavenward, trombonists bounce, the French horn player jumps up and down, between blasts down the mouthpiece, grinning with elation. They never did it like this in the orchestra at my school.

Songs come and go, repeating musical figures and themes like so many movements of the Spree's überpop symphony. Has it been hours or days? It scarcely matters. DeLaughter and his gospel show complete proceedings with an impossibly joyful rendition of David Bowie's "Five Years", and wave their emotional goodbyes. Truly, the sermon was good tonight.