While pounding the treadmill in my local gym the other day, I watched a girl group called Atomic Kitten answer the phone-in questions of their fans on MTV. With deft professionalism and emphatic Mancunian accents ("Hiya, Tracy from Oswestry, you 'avin an ace time darn thur?"), they squealed and shrieked through enquiries about clothes and celebrities. One query, however, utterly stumped them. "What did people used to tease you about at school?" muttered Karen from Solihull, her uneasy tones implying that she rarely got through a day in the playground without feeling the rough edge of some wag's tongue.

Atomic Kitten went crimson with horror. "Er, um, well," one of them admitted eventually, "um, nothing, really."

"No, nothing," chimed another.

"Actually," added the third for good measure, "I was quite sickeningly good at everything. And I had loads of mates."

"Thanks," muttered Karen from Solihull, sounding as if, the minute she put the phone down, she would be rushing off to cry or be sick. Or perhaps both.

The incident confirmed something I had begun to notice about modern pop stars. The four-times-a-week, 40-minute exposure to MTV concurrent with my gym routine is the most time I have spent observing and absorbing pop music since the end of the Eighties, when work and writing expanded to fill all the spare time I had. Like everyone else, I have registered the major changes in the pop world since, but the Atomic Kitten incident confirmed what I had begun to suspect: the weirdos have all gone.

Which is odd, because the alienated, the lonely, the eccentric and the strange were once what pop was all about. Not to mention the poor, the mad and the ugly. The British music industry was built on people who weren't popular at school - David Bowie famously owes his career-making dodgy eye to being stabbed in the pupil by a pupil with a compass. Imagine that happening to Atomic Kitten (although I'm not saying that it shouldn't).

Pop was once full of bizarrely clad weirdos, whose success validated and elevated every inhibited teenager who spent hours in a darkened bedroom worrying about being different. With Robert Smith prancing about like a punky Oscar Wilde, could any sexually confused adolescent feel alone? Or, with Gary Numan turning alienation into a stream of Number Ones, how could any Norman No Mates be ashamed? And Elvis Costello - whose oversized spectacles once caused my grandad to remark, in unenlightened disgust, "That lad looks as if he goes to a special school" - was the hero of pubescent wearers of bottle-bottoms everywhere. But, these days, with whom are the underconfident (and doubtless bespectacled) likes of Karen from Solihull supposed to identify?

Imperfection, in pop terms, is about as trendy as Brotherhood of Man. Forget the endearingly plump Kim Wilde and Debbie Harry with her chewed-looking mane of blonde hair; just as pop stars in the past were advised to have shorthand in case everything went pear-shaped, today the back-up career seems to be supermodelling. Andrea Corr would snap if you breathed on her, and Posh Spice's thighs are the size of the average wrist. Nothing there for your ordinary teenager - or even David Beckham - to grab hold of for comfort. Buying her records probably only widens the chasm between most-popular-girl-in-the-school Billie Piper and the average acne-riddled, puppy-fat-swathed 14-year-old. And the only alien thing about All Saints is that they look like something off the cover of Vogue. Which is alienating.

The men, if anything, are worse. Even the token nerdy bass player (think Craig in Bros) has been eradicated along with the exuberant campness and geisha make-up of the likes of Boy George and Steve Strange. Ironic, given that today's apparently natural-looking boy-band members have, if anything, an even freer hand with the slap - in most cases, more foundation than the base of the Empire State Building (and probably the same number of lifts). Bands from Westlife to Boyzone are characterised by a uniform, plastic perfection; even Ricky Martin and Robbie Williams, singing pigs both not long ago, have dropped pounds and now flaunt six-packs. Oasis alone fly the less than pulchritudinous flag - and look what's happening to them.

No wonder student suicide is up and there are more depressed teenagers than ever before. With the decline of the weirdo, a valuable social service has been lost, possibly for ever. Gone are the underpasses and building sites of yore: today's pop videos feature stars with perfect figures, beautiful friends and well-balanced, wonderful lives. The only weird thing about the relentlessly perfect and popular Britney Spears is her professed virginity, but that's a bit like saying the only weird thing about the otherwise catatonically bland Steps is that one of them wants to bring back hanging. It's weirdness, but not as we know it. Security is the new insecurity.

Wendy Holden's new novel, Pastures Nouveaux, is published in January by Headline (£10)