It's a good time to be Ash. After the failure of 1998's leathery, unconvincing Nu-Clear Sounds, they were facing bankruptcy, destined to be remembered as the Britpop bright sparks who burned themselves out. But their most recent album, Free All Angels, was a sparkling return to form, and now their high-profile cheerleaders include Chris Martin, Dave Grohl, the Flaming Lips and Moby.

Last week they played Knebworth with Robbie Williams, or "Gary Barlow" as frontman Tim Wheeler quipped - followed by an end-of-the-pier buh-dum from drummer Rick McMurray. At Somerset House, the goodwill is palpable. Admittedly - given the Mediterranean weather, heritage surroundings and copious beer - the crowd would probably applaud a man washing his car, but Ash offer an avalanche of good vibrations. Into their straight-up, tightly wound indie-rock they channel a jukebox's worth of three-minute pop panache. Kung Fu is the song the Undertones would have written had they been sufficiently enamoured of Jackie Chan, while Wild Surf could comfortably have been sung by the Shangri-Las.

Now in their mid-20s, Ash are still youthful enough to deliver nuggets of teenage love and loss with conviction. Youthful enough, too, to call a new song something as rotten as Renegade Cavalcade and get away with it. Wheeler is a guilelessly engaging front man, simultaneously mother-me, shag-me and buy-me-a-drink. "We wouldn't be here if it wasn't for this," he announces emotionally before Shining Light. There are limits, however. "Nu-Clear Sounds wasn't so bad, was it?", he asks at one point. A muted cheer. "Was it?" he repeats, quietly, hopefully. Oh dear, it appears it was.

Some might wonder how long Ash's Indian summer can last. The new songs aired tonight don't exactly open up a universe of new ideas, and some of their juvenilia will start sounding odd when they enter their 30s. But the crowd, jigging with boozy abandon to Girl From Mars or singing an a cappella chorus of Burn Baby Burn, are not overly concerned about Ash's future. On this long summer's evening, all seems right with the world.