Elton John, Royal Albert Hall, London

Sir Elton John is facing a backlash from conservative Christian groups after stating in an interview that Jesus was a gay man. (GETTY IMAGES)

I'm raising money for a new organ," Elton announces in his archest Carry On voice, near the beginning of this three-hour charity show in aid of the Royal Academy of Music's fund for that very instrument. Such generosity on Elton's part, from a man who can also be self-indulgent to Louis XIV extremes, is of a piece with the contradictions which power him. He has spent much of the past decade helping young musicians more directly, pushing rising hopefuls from Ryan Adams to the Scissor Sisters, and, ever since Songs from the West Coast (2001), has concentrated on re-establishing his own artistic credentials since his pop-hit power finally wilted. But the blowsy sentiment of a "Candle in the Wind" is always just a breath away.

It's just Elton and his piano for the first half of this elephantine show, with Ray Cooper to join on percussion later. When he sings, "It's gonna be a long, long time" on "Rocket Man", it nods both to the rigours of the three hours to come, and the way every arrangement is needlessly elaborated, in either his florid New Orleans boogie-woogie or mock-classical styles.

Still, this relatively spartan format forms an effective examination of Elton's art, over 30 songs, most obscure. You can hear the tin ear that makes Taupin fall short of greatness. "The war we fought wasn't too much fun", on the Vietnam-era "60 Years On", or the peacenik "He's my brother, let's live in peace" on "Border Song". But then "Your Song" enters a realm where schmaltz and genius meet. It's the song when throaty declarations of love for Elton start to rise from the darkness, from a crowd otherwise stunned by the remorseless, pianistic parade. "Rocket Man"'s outer space ennui is a pedestrian cousin of Bowie's Major Tom. But "Tiny Dancer", too, has a tune and playing of warmth and grandeur. Of the newer songs, "American Triangle", about Matthew Shepard's horrible murder for being gay in Wyoming, and "Ballad of the Boy in the Red Shoes", protesting Reagan's ignorant response to Aids, do their job decently.

This is Elton alone, unplugged and unvarnished. Walking from his piano, he can't help putting his arm up behind his frock-coat in a Napoleonic pose. Nor can he stop himself over-blowing jaunty little tunes such as "Honky Cat", or testing our stamina for him to breaking point. It's wildly uneven, punishing, and occasionally impressive, too.