Seemingly destined to expire as quickly as they exploded, Air have perhaps surprised even themselves by being that rarest of commodities: a dance act - a French dance act, no less - clearly set for the long haul.

Typically, their fourth album, Pocket Symphony, finds Air blowing hot and cold, veering between gloriously romantic slabs of delight and routine muzak. Live, the pastel-clothed duo with unsettlingly similar Neil Morrissey haircuts trod much the same course.

Studio-based pop-trance-dance is notoriously difficult to transfer to the stage. Neglecting to provide a spectacle, Air hardly aided their cause with a cheap backdrop, amateurish lighting and little in the way of talk beyond a "thank you very much" in an 'Allo 'Allo accent.

Thus, the audience were confused as to whether to dance, to watch the static figures or to chat during the plodding parts. In the end, they settled on an awkward mix of non-committal bopping and casual conversation.

When Air were substance as well as style, though, most notably on the spellbinding Run and the taut Talisman, and when Jean-Benoit Dunckel's keyboards resembled tablets of stone, they were mesmerising.

The peerless Kelly Watch the Stars, their claim to immortality, was stripped down, toughened-up and almost Kraftwerkian in its majesty, while the tub-thumping, still-adored Sexy Boy was dance music, if dance music wore Dr Marten's boots.

Taking just a solitary encore displeased the crowd ultimately seduced by the hits, but there was nothing here to suggest they won't be back.