Shobana Jeyasingh Dance Company, Queen Elizabeth Hall

It was a weird experience to get home from last night’s performance by Shobana Jeyasingh’s dance company to find Nick Griffin on TV defending his view of “indigenous” Britons. There’s a vigorous stratum of British contemporary dance that could come only from today’s fecund mixing of London and the East, and it’s the faultline where the two layers don’t fuse that makes much of this work tougher and more intriguing in intention than the more “indigenous”, in Griffinese.

Jeyasingh, with her Indian childhood and classical Bharata Natyam dance training, her 30 years living in London, and a naturally fairly austere taste, has many faultlines over which she has created dozens of dances. I used particularly to like in the 1990s how she picked away at her original image as a demure Indian classical girl, pulling it apart with tomboyish, angry young damsels tossing their long plaits dangerously and flashing their eyes in urban, wary challenges.

Her company has moved a long way; now it has white girls and brown boys, contemporary dancers and Asian classical ones, a stirpot where "Indian" doesn't always come up. Her new double bill finds her on the street, looking at black, brown and white kids, at the unconsciousness, and inextricability, of East-meets-West in urban society today.

Her 2007 piece called Faultline refracts this very well, with a sense of a furtively observed lamplit street scene, where young men and women pass through and beyond fragmented areas of light, or find a window to dance by; where a girl’s aggressive, accusatory monologue stabbing out the splayed gestures of Bharata Natyam as if attacking the shadows is followed by a looser, more contact-improvisational duet between guys.

The mood of tension is heightened, paradoxically, by the lyrical poise of the music, Errollyn Wallen’s vocal piece for the golden-voiced Patricia Rozario where her live voice duets with a version of it sampled and chequered into layers and echoes by the music engineer Scanner. You hear something echoey, poignant, long-drawn-out; you watch staccato people who seem to be rawly aware and wary of each other. It ends when they drop out of dancing and prowl in and out among each other, tight and nervy but now protective of their group, maybe their mixedness, against the gathering dark.

Faultline’s combative theme is again central in the new work, Bruise Blood, premiered this week in the Dance Umbrella 2009 festival, but this is far more resistible because of a wealth of irreconcilables. It wears its sociological heart heavily on its sleeve - the title refers to the police assault on a black Harlem man, and a Steve Reich score is remixed by Glyn Perrin with a recurrent percussive rhythm sampled from the words “bruise blood”. Whatever the intentions, the mood was certainly miscalculated last night, since the entry on stage by the featured beatbox artist Shlomo, a lanky, bespectacled bloke in big trousers, roused a roar of laughter and applause from the young GCSE-age audience (Faultline is on the school syllabus this year).

That’s not the end of the problems, though. Shlomo, like many a good musician, has an irrepressible inclination for movement, a wired, highly expressive physical byproduct of his very extraordinary vocal emissions into his mike, which all makes him much more watchable than the rather beefy European girls (made by hideous brown costumes to look even beefier) who stomp on dutifully to glare at the audience. He skips, he hops, he uses pointy finger gestures that are as much Little Italy as they are classical Indian, while the girls pose as if ordered to ape thugs going, “You talkin’ to me?”

Perhaps Jeyasingh is taking the risky option of trying to show up the silliness of the physical essentials of being menacing - or perhaps I didn't get the right end of the stick. I think of Henri Oguike’s Front Line or Mark Morris’s Grand Duo, two contemporary dances where you shudder with the menacing metaphor of the dance language, something the stage enhances, where ordinary body language shrinks to nothing in the unforgiving theatre stage.

Anyway, it’s an unequal challenge when an unselfconscious vocal star comes up against unsure dancers. Shlomo doesn’t look as if he’s dancing in a foreign language, which the girls do. I’d have liked to see Jeyasingh field her rebellious Indian classical maidens of old, with their deceptive speed and repressed passions, against Shlomo's twitches and flourishes - and see who would have been angrier. That might have a more bruising encounter between cultures, with hotter blood.

Touring details for Shobana Jeyasingh's company here. Dance Umbrella 2009 continues at various London venues until 7 November.