Keith Jarrett, Royal Festival Hall, London

"I LUV YOW KEITH!" It's not the kind of thing you expect to hear in the refined surroundings of the Royal Festival Hall, especially when the object of affection is not some callow boy-band crooner, but a respected pianist in his Sixties. And not just respected, but of a notably prickly disposition regarding audience behaviour at his improvised performances. For a moment, one wonders whether Keith Jarrett, who has just walked on stage to fulsome applause, will turn tail and stomp off again, as he has done in the past when the quality of the piano, audience coughing, forbidden photography – have disturbed his concentration.

Tonight, though, he just smiles indulgently and sets about his business. The first piece progresses from its speculative opening to a complex, rippling conclusion, with Jarrett's famous grunts and moans interjecting. Having cleared his creative passageways, the second piece, accordingly, opens in more animated manner, with little knots of notes rapped out in staccato bursts. It's much more recognisably jazz, with stalking ostinatos and subtle syncopation. It's rapturously received, as is the bluesy third piece, its wistful but generous lyricism – not to mention the way his playing lags slightly behind the beat, creating a funky undertow. But a few bars into the fourth, Jarrett stops abruptly, irritated by the audience noise, and walks over to a microphone 10 feet behind his stool to lecture us on the phenomenon of coughing, a matter that has clearly absorbed a significant amount of his attention. It appears to do the trick: after conducting the audience in a collective cough, Jarrett returns to his piano to essay a remarkable piece of oceanic cast, plunging from a surface of rippling high-register figures to dramatic, wine-dark depths.

Even before he's resumed his stool after the intermission, he bristles and walks over to the microphone again to upbraid an audience member who, despite being specifically warned against it, has tried to sneak a photograph of the pianist. "What is it about this world," he enquires rhetorically, "that demands an image?". As he returns to the piano, the tense atmosphere is relieved by Jarrett's biggest fan. "YOU'RE A GENIUS!". The pianist can't help but smile. "It's good to be loved," he acknowledges.

The rest of the concert is a bravura demonstration of Jarrett's range and ability concluding with a few encores, including a touching version of "Somewhere Over The Rainbow". By the time he leaves for good, we all love Keith.