If there's one quality that has helped Marianne Faithfull survive four decades in pop, it's a sly self-awareness. You can see it in her swaggering walk, hear it in the raw honesty of her songs, both those she has written and those she chooses to sing.
It's that quality that Jarvis Cocker seized on when he wrote Sliding Through Life on Charm, the finest track on Faithfull's new album, Kissin' Time. The song fizzes from the stage, Cocker sending chords shooting from his keyboards, Faithfull poised beneath the sparks, relishing every line.
Cocker and Pulp's Mark Webber appear in the second half Faithfull's show, the first in the Barbican's Only Connect series. For the first 10 songs, it's just Faithfull and her band.
This is problematic on two counts: the band are lacklustre, and Faithfull, though beguiling, isn't over-endowed with stage presence.
She radiates glamour as she waves her cigarette holder and gets a stagehand to reapply her lipstick. But when she nags the soundmen and attempts dreadful jokes, she is merely schoolmarmish.
What Faithfull does have is an incredible voice. It doesn't matter that she can't hold a simple tune, as proved when she serenades someone in the audience with a massacred Happy Birthday.
Her rough, fierce tones scrape at every song until the lyrics pierce the air. Times Square and Why D'Ya Do It are spine-shivering in their savagery. Beneath the ravages of age and cigarettes, though, you can still hear a girlish lilt dance through Rich Kid's Blues and Like Being Born. The contrast is heartrending.
Such a singular voice deserves more than pedestrian music, and it's a relief when the special guests arrive. Their presence is invigorating, not least because Faithfull flirts with every man who approaches her.
New York jazz guitarist Marc Ribot is underused, but brings elegant Spanish trills to Strange Weather and an incendiary quality to Working Class Hero.
Will Oldham proves a far more sympathetic collaborator; the combination of these two fractured, quavering voices is unexpectedly beautiful on the languid Dreaming My Dreams.
Even better is their version of the Bonnie Prince Billy track A King At Night. When Faithfull sings, "The Lord and I agree it's not too off to be what we are," she brings new resonances to Oldham's lyrics.
She sounds as though she has lived the song - just as a great singer should.
