Mark Steel: The angry voices of disaffected youth

Now the war on terror's falling to bits, perhaps the plan is to replace it with a war on teenagers. Almost every day there's a new announcement confirming they're an axis of evil, with news reports such as: "Police are reporting a new teenage craze of feeding ecstasy to venus fly traps, then as the poor plant desperately tries to dance they use their mobile phones to text photos of the sick stunt to their friends."

Or you get a Panorama investigation that starts: "Tonight we hear evidence that teenage gangs are going to clubs carrying small nuclear devices, which they launch at other clubbers if one of them spills their drink. One gang member, whose identity we've disguised, told us 'I had to nuke the punk man, he was disrespecting me. You should have seen that fallout man, it mash 'im up.'"

But liberal adults have their own version of teenage-bashing, a sort of "Youngsters now don't seem to care. When I was their age I was marching for the miners, but these days they have no disrespect for authority." You can imagine them waving a finger in a teenager's face and grumbling "To think - I occupied a lecture hall at Leicester Polytechnic for you - and are you grateful?"

Perhaps it's true they don't care. Few of them vote and hardly any join a political party. But a better indication of a generation's attitude towards political ideas may be the nature and popularity of its music. I've seen campaigning events ruined because the older generation are allowed to control the music. Half way through an evening for Palestinian rights, there'll be some Algerian folk singer, who says: "Now I sing song and I like everyone join in with chorus. It goes 'Everyone in my village has been shot dead'. We sing this three times and then sing 'I would rather be eaten by poisonous sand-flies of the desert than carry on living'. Now let's try practice."

Just as post-war radicals dismissed the protest songs of the Sixties as degenerate, and then hippies derided punk as ignorant, it's easy now to miss a trend in teenage music, especially hip-hop, that suggests they're more articulate and political than is normally recognised.

The difficulty is that hip-hop, on the face of it, has become a platform for promoting the adoration of advertising and wealth. If historians of the future have nothing to go on except videos from MTV, they'll be under the impression that black men in America spent all day in red silk suits, and walking across to their ex-girlfriend who's sipping cocktails by a swimming pool to plead with them to come back as they're sorry and to prove it they've bought them a BMW made out of diamonds. Then she would giggle and her nine friends in bikinis would wiggle their arses by the diving board. And in 2006 that's how everyone got through the afternoons in Harlem.

American hip-hop is so obsessed with wealth, by now the financial reports are probably read out by 50 Cent. And his next album will be calledTransfer yo' investment bonds into long-term equity before March 31st to avoid Capital Gains Tax on the interest, bitch.

But as hip-hop has become so grubbily materialistic in the country it came from, around the world it's become the angry voice of disaffected youth.

Across the Middle East, rappers display fury at the American and Israeli governments, and at their own leaders. This is the soundtrack of a modern protest movement. There are dozens of Palestinian rappers, and it's unlikely their aim is to launch a new line of trainers in Jenin.

And there'd be little point in holding a "Puff Daddy"-style showbiz party in Gaza, with the celebrities screaming "Oh look in my goody bag - a slice of bread AND a biscuit."

Similarly, across South America rap has become the youthful voice of confrontation. La Paz, the Bolivian capital, has apparently been packed with rappers since the protests that forced out the pro-American president. And in Colombia bands such as the Zona Marginals express their less-than-supportive thoughts about George Bush to a disarmingly tangoesque backing.

Obviously I'm relying on the sleeve notes to a certain extent as I don't speak Spanish, so it's possible I've misinterpreted the whole thing and they're singing "Gimme gimme gimme a man after Midnight", but I don't think so.

And in Britain the same trend has taken place, creating a hip-hop that's unmistakably British, articulate and full of opposition. The rapper Lowkey has made an album that describes beautifully the the experience of being a teenage Muslim in London since the bombings. And the eloquent Plan B deliver a powerfully moving portrait of modern London, that even starts: "Listen up you get me."

None of this would be possible unless there was at least a layer of modern youth, around the world, seething about the corporate warmongering world presented to them as the only option.

And the brilliant thing is, no older generation can go and see them live even if they want to. Because they'd instantly assume you were either the drug squad, or there to check on your daughter, or someone who should never have been released having once been exposed in the News of the World.