Paul Thomas: Britney trapped in her nymphet image

Some things can't be avoided. As the boxer Joe Louis warned an opponent, "You can run but you can't hide." Sooner or later every serious mountaineer has to have a crack at Everest. Anyone with literary pretensions has to try to read James Joyce's Ulysses. And every columnist has to write about Britney Spears. Why? Because she's a cultural phenomenon.

She's the queen of the download, the star attraction on the worldwide web. In 2003 the business magazine Forbes named her the most powerful celebrity in the world.

To understand her cultural significance we must go back to the beginning. In the video that accompanied her first big hit, Baby, One More Time, the 17-year-old Spears appears in a schoolgirl outfit that could have been designed by a committee of freaks, fetishists and dirty old men.

The titillation largely derived from the contrast between the provocative display and her baby-doll looks, a sickly package further tweaked by her insistence that she was and intended to remain a virgin. This pretence was abandoned when the discrepancy between the public tease and the private goody-good became too far-fetched to be sustained.

She followed up with a Lolita-themed photo spread in Rolling Stone magazine. With each public appearance, it seemed, her attire became skimpier, her performances more overtly sexual and her demeanour more brazen, culminating in a tongue-wrestle with Madonna.

It wasn't subtle and it wasn't pretty. Spears came to embody - and this is what made her a cultural icon - the irreversible coming-out of teenage female sexuality. Post-Spears there can be no illusions, no quaint notions of girlish innocence. The cat is well and truly out of the bag: pretty little girls turn into aggressive exhibitionists who emphatically reject the notion of hanging out for a white wedding.

(For that notorious duet with Madonna, Spears wore a wedding dress much of which detached to form a micro-skirt; like the school uniform, the wedding gown was transformed from a symbol of innocence to erotic paraphernalia.) Like every sex symbol before her, Spears was exploited by the entertainment industry even as it was making her a star. In her case, however, there was more to it than the marketing juggernaut that pushed all those millions of albums, posters and screen-savers.

Unlike her predecessors, Spears was still a girl - and knowingly presented as such - when she acquired sex symbol status. The problem with making a girl a sex symbol is that you're inviting the male audience to see her, first and foremost, as a sexual being. Spears' lasting cultural significance lies in the extent to which girls follow her example and males draw the obvious conclusion.

Having stamped her mark on society, Spears withdrew from the spotlight to become a mother.

There are a number of ways of interpreting this development. One is that she's simply continuing to compress the female experience into the shortest possible time-frame. At this rate by the time she's 40 she'll be a golf-playing granny lamenting the amorality of the younger generation.

Another is that by taking a sabbatical from show business to have children, Spears is repudiating her earlier incarnation and its core value of flaunted sexuality. Or maybe she just likes kids. Time will tell.

What's already clear, though, is that the mass media doesn't approve of her transformation from nymphet to suburban mom. These days Spears' media coverage focuses almost exclusively on her shortcomings as a mother. In February she was photographed driving with her eight-month-old son in her lap. In the past couple of weeks she's been hauled over the coals by the rent-a-quote "experts" for not properly strapping poor little Sean Preston into his car seat and stuffing him with ice cream to make him go to sleep.

Last week she stumbled outside a New York hotel causing the mite's head to be flung back and prompting a fresh round of tut-tutting that included comparisons with Michael Jackson's infamous baby-dangling, even though one was an accident which occurred on the pavement while the other wasn't an accident and took place on a fifth-floor balcony.

We don't know how self-aware Spears is or whether she's fully in control of her life. Incidents such as the 55-hour marriage to a childhood friend suggest that her personal life is as impulsive as her career was calculated.

But once you become a megastar, you no longer have control over your image and Spears is now discovering the difficulty if not impossibility of abandoning or toning down a persona that has had such cultural impact and generated such profit.

She won't be allowed to be just another mum, learning on the job and kissing her babies better when she or they have a little accident. Because of what she was and perhaps a lingering puritanical notion that sex symbols, by definition, are deficient in maternal instinct, she won't be allowed to raise her kids in private.

One can only hope that this frantic melodrama doesn't turn tragic in the third act and Britney Spears doesn't end up like so many products of the dream factory whose farewell performance is to disintegrate before our eyes.