I’ve got the breasts of a 16-year- old,” Ulrika Jonsson bragged this week as she displayed her extensively remodelled physique on Californian sands.

Ulrika, love, you haven’t. You’re 41. Your breasts, like the rest of you, are heading into middle age. What you most definitely have got, on the other hand, is a bad case of extreme selfdelusion mixed with money, me-time, an inordinately high pain threshold and the determination to look half your real age. You are, in other words, a youthaholic.

And you are not alone. Take Demi Moore. Entirely rebuilt a few years ago, at 46 she now not only looks younger than her thirtysomething husband but also, spookily, her own teenage daughters.

Madonna, of course, stops at nothing to ensure that age shall not weary her nor the years condemn, whether or not her gym-honed arms look more gnarled than tree branches in winter. Even Michelle Obama, 45, and near-perfect in practically every other respect, has a serious gym habit, wears tweenage neon belts and has upper biceps that sparked an all-new type of American arms race.

Other fully paid-up youthaholics include Elle Macpherson, still doing big hair, tiny dresses and wrinkly knees at 46. Victoria Beckham, meanwhile, goes shopping in microshorts with her young sons despite being well into her fourth decade. It might have been to punish them for something but I suspect she was serious. Even Cher couldn’t Turn Back Time — and few people, let’s face it, have tried harder.

The trouble is, where celebrities lead, the rest of us follow. The result is that we’ve all now bought the idea that one can look as dewy as a morning rose well past the menopause. I used to work with a woman whose greatest boast was that she could fit into the same size Miss Sixty jeans as her daughter (and frankly, she was nearer Sixty than Miss). Another friend has no secrets from her husband — apart from her Botox dependency.

Yet who am I to talk? I was 44 last birthday and only last week a friend steered me away from a peony-printed minidress: “Florals,” she murmured, “so ageing.” Most of my make-up routine is spent trying to find a shaft of daylight that’s gentle on my wrinkles while still being possible to see in.

I spent a fortune at my dentist on those whitening trays that make you look like Jaws from the Bond films and which I daren’t use in case the children see me and are scarred for life. I’ll be blonde into my eighties, hot-pink toenailed into my nineties and the silver lining to the recent flu epidemic was, for me, finally losing that pesky half stone. But then, age has always been a moveable feast (or diet). In the 1970s, when I was little, women of 30 looked more like 60. In the 1960s, girls of 20 looked 50 (as any old Beatles newsreel attests).

It’s the other way round now. Fifty, as we’re endlessly being told, is the new 30; 40 the new 20 and so on. Perhaps it’s less that we’re vain; we’re just confused or unable to add up.

We probably should try to, though, because it’s getting beyond a joke. Thanks to the youthaholics, we have swallowed wholesale the suggestion that the toughest old mutton can pass as the tenderest lamb with the aid of a Power Plate, a spot of collagen and a session with the St Tropez and paper pants. We are starting to believe that loveliness equals youth alone, or at least the illusion of it. Beauty has become one-dimensional, or even half-dimensional; like a size-zero model, you can’t see it sideways. The idea that beauty is about what’s inside as much as outside is fast disappearing, possibly because there isn’t anything inside except edamame beans and we’re all too hungry to think. Intelligence, humour, personality, wisdom, kindness, individuality, warmth or ambition — except to look 12 — no longer, it seems, has anything to do with beauty. Ageing, meanwhile, is a confusing mess; the true and natural order of things, skew-whiff.

Youthaholicism is not, of course, confined to women. Look at poor old Sarko, jogging to collapse to keep trim for Carla. Or the mahogany, raven-locked Simon Cowell. But there’s no doubt that women are the main victims. Given that there isn’t (yet) a Priory for youthaholics, I’d like to suggest my own 12-step programme. This would include forbidding the exposure of knees or cleavage after 40, upper arms after 50 and a cut-off point for long hair at 35. Escalating plastic surgery dependency would be addressed by solitary confinement in a cell plastered with pictures of Joan Rivers and Jocelyn Wildenstein. Youthaholics would be discouraged from Topshop the way alcoholics are discouraged from pubs.

Self-esteem, meanwhile, would be rebuilt by looking to other celebrity role models. People no less successful and attractive but who seem to have come to come to terms with time a tad more gracefully. Let’s call them the Agebusters: Kim Cattrall, fiftysomething and bitchslapping Botox in a surprisingly un-Sex and the City manner. Then there’s Michelle Pfeiffer, throwing out the miniskirts — “it’s not that my legs are bad, it just looks silly. I’m 50 — who are you kidding?”

It’s a question more people should be asking, it seems. Agebuster or youthaholic. I know which looks better to me.

Beautiful People by Wendy Holden is published by Headline Review in paperback, £6.99

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