The Gossip, Shepherd's Bush Empire, London

After more than half a century of rock'n'roll, properly subversive gestures are quite difficult to pull off. But at the climax of an astonishing show, The Gossip's volcanic frontwoman, Beth Ditto, engineered one that provided yet another reason to mark her down as a true great.

The job of security on these occasions is usually to keep the audience off the stage. This time, it was the other way round, and it wasn't just a lucky two or three who were let on.

Signs that something was up came when Ditto stepped forward and bent the ear of a member of the venue's staff who was patrolling the front row. And as the band launched into their biggest hit, "Standing in the Way of Control", the people started coming. Ditto herself was doing all she could to pull them on to the stage until it teemed with audience members – maybe 300 of them, all dancing like crazy – and the band had disappeared from view. It was tumultuous, and unforgettable, and it rounded off surely one of the most explosive hours of live music London will witness all year.

Such moments are all of a piece in a career in which Ditto, the modern music scene's No 1 gay icon, has rewritten so many rules – about how pop stars should look, and conduct themselves, and treat their audience – while establishing the truth that blazing honesty is the only real basis for the acquisition of cool.

What made the encouragement to invade even more extraordinary was that earlier in the show, Ditto was scathing about the lack of response she thought she was getting. "We've just been in France," she said. "They don't speak the language. But if I say, 'Clap your hands,' here, I mean clap your hands!" For a while it was as if the audience was too awestruck to give back.

None of this would amount to anything if Ditto didn't possess a staggering talent. Her voice is somehow an amalgamation of every tragic female vocal genius you've ever heard. She soars sweetly like Patsy Cline, she howls like Janis Joplin, she thunders like Tina Turner, and she seems to suffer like Maria Callas. And can she dance! Yet it's all completely free of artifice. Ditto performing in front of thousands of people is like Ditto performing in her bedroom.

Ditto cut a figure that was somewhere between a creation out of John Waters and a character that never quite made it into The Simpsons. She wore a short green dress that threatened to come apart under the pressure of her physique, and elegant, non-matching (red and gold) low heels. Her mass of dark hair was done up in a perm.

With her were guitarist Brace Paine and drummer Hannah Blilie, and between them they cooked up an exhilarating, tight, heavily lacquered sound that straddled punk, soul and the kind of swamp rock pioneered by Eighties legends The Cramps, a similarly over-the-top band whose blend of humour and danger is an essential characteristic of the Gossip.

From the irresistible dancefloor bounce of "Yr Mangled Heart" to the deeper, darker waters of "Coal to Diamonds" – a stupendous ballad that was perhaps the best showcase for Ditto's enormous voice – The Gossip have musical range as well as shedloads of attitude. "Jealous Girls", reeking of late-Seventies CBGBs, sounds like the greatest hit Blondie never had, and "Yesterday's News" is adorned with a joyous, lilting guitar motif.

And then there was "Standing in the Way of Control", one of those songs that, if Ditto had never written or recorded anything else, would forever stand proud on the pop'n'rock landscape. A gay anthem that is an "I Will Survive" for the 21st century, it has echoes of Gloria Gaynor's classic and is every bit as defiant, but its sheer generosity of spirit and unstoppable forward propulsion make it somehow even more. Truly, Ditto is the gift that keeps on giving.