In an Islington pub for pre-gig drinks, I order that unpretentious student/goth classic, a snakebite-and-black. Because this pub has delusions of grandeur, the drink comes served in a goblet of engraved glass, an elegant setting belying the cheap and giddy good time that swirls in its velvety depths. As a stylish repackaging of the marginal and derided, it’s quite an Amanda Palmer way of doing things.

Across the street on the forecourt of the Union Chapel, a man with the dress and demeanour of a Victorian undertaker is peddling on a contraption of polished wood that might be a piano, might be a hearse. Slightly too-large-for-comfort sockpuppets are carried by men in black. The circus is in town, gloriously, and chancing across a beauty parlour full of sailors wouldn’t come as any great surprise. On the rows of wooden pews inside the venue, clusters of Palmerettes bloom like a thousand flowers: dark-eyed, candyfloss-haired, irrepressible and remarkably dressed. Amanda Palmer gigs are no bad place for the self-conscious, though; from the moment our hostess takes to the stage, resplendent this evening in a full-length swathe of black and white stripes, you can be fairly confident that no one’s looking at you. Although the evening features question-and-answer sessions and the auctioning of a painting completed during the show, this is less the Amanda and Friends Musical Cabaret that other of her gigs are more accurately billed as. Both the setting and her performance tonight ensure that the spotlight can barely drag itself away from her.

I often forget that the piano is a percussion instrument. In this respect Palmer’s playing is a revelation, a hammering out of powerful, authoritative notes that drill her words into your hindbrain. As a vocalist, she deserves superlatives that haven’t been invented yet; ‘Brechtian’ doesn’t come close, and neither does ‘punk’ or ‘cabaret’. Her voice tolls like a church bell, its dramatic depth and texture punctuated by the lightning-quick criss-cross of her hands on the keys. Her delivery of the songs tonight veers between imperious intensity (the stabbing staccato of ‘Runs in the Family’, or her nigh-on terrifying, breakneck cover of Jason Webley’s ‘Icarus’), and a yearning vocal caress which lights up ‘Boston’ and contrasts with the lyrical violence of ‘Delilah’. And then there are extraordinary, almost uncapturable moments, like her Struwwelpeter cover or the piece of Bach she plays after a typically nervy and self-effacing introduction. Her revelling in music is infectious and, like all too few artists, she concentrates on giving back as much enjoyment and enthusiasm as she inspires.

(There’s a lot to be said about whether it matters, and how much and why, that Palmer is a female artist. Talking before, during and afterwards with starry-eyed provincial girls who’ve made a pilgrimage to London for this gig, hearing them freestyle her Palin-baiting lyrics and indulging in unashamed pansexuality – of course it matters. When I was the age and in the dire smalltown straits of some of this crowd, there was no one comparable in the public eye to entertain, affirm or inspire. I had no one to nail the absurdity of street harassment with the crucifying accuracy of ‘Ampersand’, and nothing approaching ‘Bank of Boston Beauty Queen’ and its wry dissection of the rewards of self-actualisation. And so, as a female and a music fan, I’m grateful for her. But in many other ways, Palmer is a transcendent, liberatory force of nature, and the media she chooses matter less than the message.)

Back to tonight. The incongruous candlelit venue is ripe for subversion, and she takes great pleasure in having her charming companion deliver Derek and Clive’s profanity-ridden parody hymn. Later, the magnificent ‘Oasis’ becomes a sacrilegious sing-along, complete with happy-clapping and exuberant shouts of ‘CRACKWHORE’ from the congregation. The encore, however, sees her stand stock-still, hands clasped before her like she’s ready to recite at Sunday-school, and perform an astonishing unaccompanied cover of Tori Amos’ ‘Me and a Gun’. Clear-eyed and spine-chilling, it’s a no-but-seriously flipside to ‘Oasis’ that makes the crowd collectively catch our breath. The crystalline version of ‘The Point of it All’ which follows, heartwrenching enough on its own terms, seems more affecting for being something of a conduit for the emotions held in check throughout the previous song. A subdued but stunningly powerful final note, it sends me back onto the still-unreclaimed street rejoicing in faith reaffirmed. Praise be.