THE boundary between Bethnal Green and Hackney is not the most salubrious of places. Next to the railway tracks, half of which are now disused, rusty yellow gas towers cower beneath a leaden sky. Minicab offices and cheap takeaways crowd the pavement, wasteground is littered with scrap metal and detritus, and the crumbling buildings appear to be making a last, valiant stand against the property developers who are encroaching from the west, having already turned much of London's traditionally working class East End into a paradise for affluent twentysomethings.

This, though, is where Lady Sovereign feels at home. Raised in a south London council estate and kicked out of school at 16, she's spent the last three years of her life working here, in a fortress-doored studio on the fifth floor of a grimy block. We meet at the greasy spoon around the corner, at whose plastic tables she eats lunch every day. A diminuitive 19-year-old MC with a machine-gun delivery, Sov - as she likes to be called - is one of the world's most indemand rappers. Hip hop titans like Jay-Z, Snoop Dogg, Pharrell Williams and Missy Elliott, as well as British acts like Basement Jaxx and up-and-coming ska rockers The Ordinary Boys, are clamouring to work with her.

It wasn't always like this. Born Louise Harman - though she "can't remember" the last time anyone called her that - Sovereign was something of a loner, growing up on Wembley's Chalk Hill estate. School, she says, was "shit, just shit".

"Teachers hated me. I got the blame for everything, even the things that I didn't do, " she says, with enough humour in her voice to hint that there was at least some misbehaving. "It was horrible, horrible, I couldn't get on with anything, so I started bunking school. I just couldn't be arsed to go."

The only thing she loved was football.

She was good, too. "I had trials for loads of women's football clubs when I was about 13. I even got asked to come and try out for the Arsenal FC ladies team. Didn't go, though. I was too scared to ask my parents for the money to go." She still plays now and again, though "the smoking gets in the way a bit" she says, toying with her pack of cigarettes. (Sovereign brand - it's where she got her name. ) "I played in this celebrity six-a-side thing the other week, " she continues, as if the idea of her playing celebrity football is not far shy of absurd. And how did she get on?

"My team won, " she says. "It was me, and the girls from [manufactured pop group] Liberty X. Who else? Couple of models. I showed them all up, man, if it wasn't for me they'd never have won. The other teams were all girls from Corrie, people who you see in Heat magazine. Everyone else was dolled up and pretty and . . ." She mimes a particularly girly kick. "Kicking the ball like that. But I just went down there looking scruffy in front of the photographers, and I was a bit drunk when I was playing. Every time a game finished I'd go to the bar and have a vodka and Red Bull. Maybe that helped a bit."

At 13, playing football was the only thing that got her any attention at school. "That was the only time they ever wanted me in school, or would be nice to me, 'cause I could help them look good.

But in the classroom, forget it.

Maths lessons or whatever, I wouldn't get on with anything and they wouldn't encourage me to do it, so I thought, why am I even bothering?"

Music lessons weren't much better - "why were they always teaching us about Beethoven and Mozart, asking everyone to play this song on the keyboard? I was wanting to learn about the proper history of hip hop and dance music and they were just saying 'well, this note sounds like this, and that note sounds like that'."

By the time she was 15, Lady Sovereign was writing already lyrics of her own, feeding off the rhymes and rhythms she heard on the local pirate stations. ("They were all I had, " she says, "I didn't really go to clubs 'cause they would never let me in anyway; I still get trouble now, even though I'm 19.") She kept the music quiet at first - though not because of nerves. "It was just a case of would [my parents] take me seriously, because it was pretty unexpected; they thought that all I wanted to do was play football and they didn't know I had this talent. I kept it away from my family for a bit.

I wanted to keep it apart - I locked myself away when I was writing 'cause I like to be on my own and do it all myself."

After being kicked out of school, she joined a drama group at the suggestion of her father and was cast in a short educational film about a bored teenager with hopes of being a rapper. "I swear, it was like my life up there on the screen, " she says with a laugh, "this girl who didn't go to school, who was an aspiring DJ and MC." A chance to contribute to the soundtrack was all she needed, and her fast-developing confidence and quickfire lyrical style received the boost it needed.

The director passed Lady Sovereign's work to a friend of his, a producer friend called Medasyn, whose work with various rappers was getting ever-increasing amounts of critical acclaim. (Musical talent evidently runs in the producer's family; his real name is Gabriel Prokofiev, his grandfather was the great composer, Sergei. ) Medasyn, says Lady Sovereign, was "the first person to let me inside a studio", and he's still her main producer, conjuring the multi-faceted tracks over which she lays down her rhymes. Even now, she sounds as if she knows the introduction was a one-off piece of luck.

She would occasionally get slots on pirate radio, but in the male-dominated "grime" scene in London, where the music is a brutal distillation of hip hop and jungle's murderous bass sounds and spartan, syncopated rhythms, she opted to exploit the internet instead, posting her tracks on fan forums and websites.

A couple of limited-run single releases, and a few brief live dates in London and Scotland later, she was signed to Island Records, and producers were begging to work with her. Rap mogul Jay-Z heard rough cuts of some of the tracks from her forthcoming debut album and demanded she fly to New York to work with him. "I did some stuff with him and he's hooked me up with producers and stuff, and it was great to meet him, he's just pushing [my music] and backing it."

She says all this nonchalantly, as if Jay-Z and Pharrell Williams are just two everyday punters who caught her on the radio.

"It's nice, " she says almost sheepishly, "but like, I don't really talk about it with my mates unless they ask me. I get excited but in my own way, I keep it all to myself. I think about it at times, when I need to, but I'm not jumping up and down."

Partly, she says, she doesn't want to jinx what's already in the pipeline. "I don't want to get too excited, and then find everything tumbling down, 'cause I'll feel like a bit of a plonker, and I'll get laughed at. So I don't really show my excitement."

Coming from someone whose energy levels are somewhere between jittery and manic, this seems hard to believe. Lady Sovereign constantly fidgets. With her lighter, with her trademark fat sovereign ring, with the chain and keys around her neck.

She mimics a cat's yawns and miaows as she walks, briskly but with an insouciant slouch, down the street. She's constantly on the move, even when sitting down, and this energy infuses her live performances, which she describes as "half MC-ing, half improvised stand-up".

Sovereign sings about life on the estate where she grew up; she sings about being cheeky and a bit wayward; she sings about the demonisation of her beloved hoodie, and how she's none too keen on being labelled a chav.

"I just find it so f***ing stupid that they're trying to ban a piece of clothing that's been around for so long, " she says of the controversy which led to shopping centres banning hooded tops. (She's set up a "Save The Hoodie" campaign as a protest. ) "Y'know, it's fine for grannies to wear bonnets, or for blokes to wear baseball caps, but step inside wearing a hoodie, and it's, 'Get out or take it off '."

Similarly, it "gets on her nerves" when people "are making money out of the whole chav thing, like websites are making a packet out of disrespecting people's way of life. It's horrible, really, and it's similar to racism, but they can get away with it. I mean, I don't mind it too much when someone calls me a chav, but some people take it too far." Once, spotting an offending journalist, she set off in pursuit of him.

"He'd written something really horrible about me, calling me a pikey chav princess or something like that, and I thought that was a bit harsh. And so I chased after him, and he just legged it."

At 19, Lady Sovereign may have moved out of her parents' house and into a flat of her own in Earl's Court, and be legally able to buy her favoured vodka and Red Bulls, but she's still a kid, though one whose tenacity was bred on a council estate she's never going back to.

"I still like where I grew up, but they just demolished it and rebuilt everything so it's all clean and tidy and not how it was, " she says. "It's a bit upsetting going back there."

If things go according to her non-existent plans - "I don't like to think about things too much" - the coming year will see her conquer the UK scene and take the battle to America.

She claims she'll never change, though, no matter how many hip hop superstars want to work with her. As for those who treat her differently, now that she's in demand: "It confuses me a bit, it's like, come on, just treat me for who I am, not because of what I'm doing." She pauses, and adopts a harder, more defiant tone of voice. "But I haven't. I haven't changed at all. My lifestyle's changed and that's it." She looks out on to the road across the street from her favourite greasy spoon, at the gas towers, the railway arches, the graffiti, the battered signs with missing letters. They still feel like home.

Lady Sovereign plays Cabaret Voltaire, Edinburgh on November 3; Snafu, Aberdeen on November 4; ABC, Glasgow on November 5. The single, Hoodie, is released November 21 on Island Records www. savethehoodie. com