"The biggest midget in the game," all 5ft 1in of her, is no longer the gauche grime-girl from Wembley. Dropping in for one UK show before setting off to support Gwen Stefani's American tour, this is a slicker Lady Sovereign than the one who went to try her luck in the US a year ago.

Only the second non-American rapper to be signed by Def Jam Records, she's spent an intensive six months acquainting US radio with London vernacular, and it's had an effect. Her flow is more seamless than before, her swagger more confident, and when she roars: "Make some noise!" it's with the air of someone who expects to be obeyed.

Sovereign - or "S-O-V", as fans at the front have it - is promoting Public Warning, her much-delayed debut album. Its lengthy gestation has caused her to be more or less written off in the UK; there's decidedly less hype around this show than there would have been 18 months ago.

If she puts on more gigs like this, though, she can turn things around. Despite repeatedly claiming to be drunk - an apparent point of pride - she's as sharp as her lyrics, whipping out rhymes the Daily Mail would take as confirmation that the world is going to hell in a handcart.

"Police carry guns, not truncheons, make your own assumptions/ London ain't all crumpets and trumpets, it's one big slum pit," she barks in My England - then defuses the impact by singing happy birthday to her DJ.

Abetted by a drummer and a bassist, who produce a grime-ragga hybrid as sluggish as boiling tar, Sov is merciless. Screwing herself into a coil of disgust, she dedicates Tango to "orange" fake-tan fans, and takes a ferociously heavy cover of the Sex Pistols' Pretty Vacant as the signal to scream until even the sound engineer twitches. Completely punk at heart, Lady Sovereign would have made a great Sex Pistol. It's probably best not to get in her way.