MIA, ICA, London

The Sri Lankan-born, London-based, agit-rapper MIA's success seems to be built around confounding expectation: her abrasive, ghetto world-music beats are more than brainless dance music; rather, they are barbed insights into rarely heard countries and voices.

"Bamboo Banga" is a case in point, as MIA shouts out to "Somalia, Angola, Ghana, India, Sri Lanka" over snappy dancehall beats. It's followed by "World Town", a clarion call to dance, with the chorus "Hands up/Guns out/Represent the World Town".

As a frustrated film-maker, it's no surprise that MIA's show leans heavily on visuals. At times it's like looking at a super-sized version of her MySpace page, a non-stop flurry of colours and imagery: machine guns, CCTV footage, satellite maps and street kids.

With MIA creating sirens, gunshots and handclaps from an effects box, and the audience blasting horns, it's a thrilling rave-cum-gig. MIA is a bundle of energy, urging the audience to follow her lead, and demanding noise ("Turn up the heat or get out!").

"Pull Up the People", from her debut LP Arular, sounds like a cheeky mission statement as she declares, "I got the bombs to make you blow". She reveals that she wrote "Sunshowers" (about bombs) before London's Tube attacks, and in this context it finds new depth and relevance.

She invites girls from the audience on stage for "20 Dollar", and 40 boys and girls oblige; like MIA's music, it's chaotic but it works. "Hussel" sees Afrikan Boy a Londoner who raps in a Nigerian accent offering illegal immigrants an insight into making money.

An extended intro leads to the riotous baile funk anthem "Bucky Done Gun", and the stage invasion happens again in "Boyz", with Afrikan Boy leading the "row the boat" moves while MIA demands that the volume be turned up. "Paper Planes", a moving, psychedelic lull, is shattered by the till ringing and gunshot of the chorus sung by kids, "All I want to do (bang bang)/Is take your money (kerching)".

MIA is often derided as style over substance, but there is no denying that she's a distinctive figure in modern music: she's taken hip-hop's defining principles and made them relevant again by cobbling entirely new music out of what already exists. What she's created is an audio-visual lingua franca, or supra-national music, which communicates directly to a generation that has only known the world as a global village. And for this generation, she's a star.