On an it-takes-one-to-know-one basis, I’d say the new British singer Lily Allen is a classic middle child. So she’s grown up feeling, fairly or unfairly, that she was sort of left to get on with it — and as a result, her inner world is as highly developed as her self-absorption is total. Doubtless her siblings would take issue with her version of events (they always do). But for Allen, how she experienced her early years as a serial expellee from several schools, and her frustration at not being able to press fast-forward and become an adult immediately, has not so much informed what she is now as sculpted every last detail.

And what she is now is a young person, just days away from her 21st birthday, who is having to get used to the idea that those years of self-absorption are suddenly bearing fruit, in the shape of a nice fat record contract and her status as the reigning queen of MySpace.com. Used to heavy fretting, she is being forced to cope with a clear absence of things to worry endlessly about. Her lilting, ska-inflected songs, whose lyrics look at London life, its triumphs, tribulations, silver linings and vicious flip sides, attract listeners in their tens of thousands to the website (which is owned by The Sunday Times’s parent company, News Corporation).

“I’ll always have low self-esteem, I think,” she says matter-of-factly. “I’m just that sort of person. I come from a neurotic family. You feed off who you’re surrounded by, don’t you? I mean, I feel good at the moment, but I never really think of myself as having done something brilliant. I still feel like I’ve blagged all of this.”

A gamine pugilist, Allen — the daughter of the actor Keith Allen and the Oscar-nominated film producer Alison Owen — is the personification of her songs. At once carefree and careworn, she communicates an air of casual indifference and granite determination. When she sings, on her new single, LDN, “Sun is in the sky/Oh why, oh why would I want to be anywhere else?”, she conveys a powerful ambivalence about her home town. But her sly, spry street poetry has its detractors.

“Someone sent me this thread from this f***ing evil website,” she recalls, “and it was going on about my dad — ‘Nepotism still rules. The fact that she talks about pimps and crack whores as if she’s just walked off some council estate is galling.’ But it’s not meant to be about me and where I come from. It’s about, yeah, we live in this amazing city, it’s really cosmopolitan and brilliant in lots of ways, but it’s quite sad that you have to drive past Kings Cross and see all these whores in miniskirts, or read about grans getting mugged by 15-year-olds.”

Her huge popularity on MySpace helped her get her record deal; it has also enabled Allen to ward off the less welcome suggestions of her label. “They tried to put me in with a load of pop writers, and it never works, it just sounds really contrived. It was only when I put the stuff on MySpace and everyone suddenly started going crazy for it that they suddenly got the confidence again, and it was like, ‘Actually, you are quite clever, this could work.’ So MySpace has A&R’d my record.” She comes up with a slogan, as befits someone who specialises in nifty rhymes: “I like MySpace ’cos it’s such a nice space.”

On the same site, the singer names her favourite listening: a very 2006, iPod-shuffle collection that encompasses everyone from the Specials, Minnie Riperton, Bananarama and Chas & Dave to the Streets and Arcade Fire. She also gives good blog, railing against radio DJs, apologising to ex-boyfriends, bemoaning her alcohol consumption and slapping down her record company. “Nothing like a few meetings with music-industry heads to destroy what’s left of the creative juices,” she writes at one point. Today, she’s more diplomatic: “I love them dearly because they give me money and have confidence in me,” she says, adding, “I just hope they pick me up for album two.”

Confidence is clearly a problem for this likeable and contradictory individual: it’s both sky-high and wafer-thin. She’s cheeky enough to sneak her own songs onto the mix tape she placed online, alongside the likes of Dizzee Rascal, Rod Stewart and Squeeze. But she will also say: “People are so horrible, especially in London and within the industry I work in; but on MySpace, people are just telling me how brilliant I am.”

After years of unhappy-go- unlucky, Lily Allen is learning to get out (of herself) more. God knows how she’ll cope if she achieves the sales many predict for her. “I don’t want to write happy, chirpy songs, because I’m not a happy, chirpy person,” she concludes with a cackle.

“It has to be twisted.” Typical middle child: always with the complications. Then she says: “I feel ridiculous talking about myself.” Yeah, right.

LDN is released tomorrow on Regal

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