Wendi Deng, 48, was spotted recently hand-in-hand on a beach in St Barts with hunky 21-year-old model Bertold Zahoran (pictured)

Forget the latest designer handbag. For a whole raft of middle-aged female celebrities, there’s only one fashionable accessory you need to dangle on your arm — and that’s a toyboy.

From Madonna to Susan Sarandon, Kylie Minogue to Wendi Deng, Kate Moss to Mariah Carey, it seems more and more women of a certain age are falling for the charms of men years — and in some cases, decades — their junior.

Just this week, Kylie, 48, announced she would take the surname of her 29-year-old fiancé, Joshua Sasse, when they marry. Wendi Deng (the sleek former wife of octogenarian tycoon Rupert Murdoch), 48, was spotted recently hand-in-hand on a beach in St Barts with hunky 21-year-old model Bertold Zahoran.

Kate Moss, 43, is romancing Count Nikolai von Bismarck, 29, while 51-year-old Net-a-Porter founder Natalie Massenet is dating fashion designer Erik Torstensson, 38.

The toyboy trend isn’t just reserved for celebrities, either. According to one recent U.S. study, almost a third of single women between the ages of 40 and 69 are dating younger men, with ‘younger’ defined as ten or more years their junior.

So, what’s causing this boom in toyboys? For some of the celebrities mentioned, there’s an undoubted desire to attract attention and controversy.

Fast approaching 60 and with a seemingly unquenchable thirst for men 30 years (or more) her junior, Madonna never shies away from an opportunity to display her passion for men who could easily be her sons.

Indeed, she revels in it, telling Harper’s Bazaar magazine recently: ‘I have lovers who are three decades younger than me. This makes people very uncomfortable.’

Certainly there’s still a stigma against women — especially those in or beyond the menopause — dating much younger quarry.

And let’s be honest, it’s not just men who judge. The relish with which these women scoop up toyboys unnerves many others who would recoil at being labelled a cougar — the nickname for a predatory older woman seeking a sexual relationship with a younger man.

This week Kylie Minogue , 48, announced she would take the surname of her 29-year-old fiancé, Joshua Sasse, when they get married (both pictured)

Because while it’s one thing to swoon over the six-packs of Aidan Turner in Poldark, James Norton in War And Peace and Tom Hiddleston (aka Hiddlebum) in The Night Manager, it would be quite another to invite one of them, or any young man, into our beds. Wouldn’t it?

But then much younger men have never really been my thing. The three years I have on my partner is quite enough, thank you. It certainly seems that fewer of us feel this way, though.

While older women have always fallen for younger men, the sheer amount of cradle-snatching A-listers at the moment suggests something of a societal shift.

And, fascinatingly, it’s one that reveals as much about the diminished status of men as it does the increasing dominance of older women.

For middle-aged women have never been more sexually powerful. My peers in their 50s and 60s are far more outward-looking and dynamic than those of our mothers’ generation, who would have been utterly shocked by any relationship that didn’t have the man firmly in the senior position.

With the armoury of tweaks and tucks at their disposal, and booming gym memberships — not to mention perked-up sex drives and plumped-up skin courtesy of HRT — older women today are looking and feeling a lot more youthful than our mothers were at the same age.

Little wonder that this generation of Mrs Robinsons is proving so alluringly sexy and sophisticated that bedazzled young boys are seemingly becoming their willing slaves.

I use the word ‘slaves’ pointedly. Because with the rise of the potency of middle-aged women comes an equal and opposite reaction: the infantilisation of men.

Net-a-Porter founder Natalie Massenet, 51, is dating fashion designer Erik Torstensson, 38

Today, attractive young men such as Wendi Deng’s toyboy Bertold Zahoran play the same role as previously enacted by pretty young girls with their wealthy sugar daddies.

Their job is to be sexy, obedient and biddable. The sugar daddy is dead. Long live the sugar mummy.

It’s a fascinating change in gender relations — and one rooted in economic and sociological realities.

One of the fundamental tenets of evolution — men being attracted to younger women because they are fertile and women being drawn to older, higher-status males who are in a better position to provide for offspring — is slowly being eroded.

Instead, says social psychologist Alice Eagly, professor at Northwestern University, Illinois, the profound changes in our social roles are in turn twisting our sexual interactions.

Gone are the days when middle-aged women would adopt skirts of a sensible length, allow grey hair to creep in or take a back seat in public life.

Today, they’re still working in powerful positions, are financially independent, are adept at holding back the ravages of time — and are often newly single, thanks to divorce.

Their lives are completely different from granny sitting in her easy chair. For the first time, they’re an attractive sexual proposition — and this, says Eagly, will create a permanent difference in the way we live.

Eventually, she says, it will seem utterly natural for older women to enjoy the social status that was previously reserved for men.

And with this increase in power, many middle-aged females will adopt previously ‘male’ behaviours.

According to Eagly, the impact of this could be vast, turning the world on its head and causing our whole definition of femininity to change.

So the latest spate of cougar A-listers could be seen as the vanguard for this new mode of femininity — one where it’s ladylike to pay your man’s bills, flaunt a pretty young male thing on one’s arm and choose your mate on the basis of his cheekbones rather than his chequebook.

Supermodel Kate Moss, 43, is romancing Count Nikolai von Bismarck, 29 (pictured)

It puts those ‘real men’ who still hold doors for women and wouldn’t dream of their date paying the bill under threat as never before.

Meanwhile, attractive younger males, who are more likely to fit in with their super-successful female partner’s schedule than an equal player with his own established work patterns and responsibilities, will be more sought after in the middle-aged dating marketplace.

Indeed, the very fact that middle-aged women are more likely to have a high status can drive them to seek out younger partners.

According to dating coach and behavioural psychologist Jo Hemmings, living in a youth-driven world puts new pressures on women.

‘There’s a constant need to reinvent themselves, to ensure they’re being current and still relevant,’ says Hemmings.

‘And one way to get this validation — to hold onto their prime and to prove they’re still desirable — is to be seen with someone much younger.’

This is not to suggest, says Hemmings, that the likes of Madonna are acting cynically in their choice of lovers.

Rather they’re drawn to the kind of young men who can trick them into believing that the years are standing still. After all, there would be no hope of that if they went for a man their own age.

Many of the newly retired men I meet are content with their comfy slippers just as their wives are bursting forth with a post-menopausal, post-empty nest lease of life, taking on new challenges and seeing the next stage as something to look forward to rather than the slippery slope into dotage.

So it’s not surprising if more and more middle-aged women hanker, a little wistfully, after younger men. And that an increasing number are willing to go beyond the fantasy and actually do something about it.

When one of my friends divorced a few years ago, she took a lover, Max, who was smart, funny and ten years her junior. When she asked him how he felt about her being 61 to his 51, he replied: ‘That’s easy — you’re so much younger than me.’

She added: ‘He tells me I’ve opened his eyes to a more youthful life, and he seems to be loving it.’

I wondered if leaving behind a 25-year marriage had contributed to her sense of vigour. ‘For so long, my ex was busy telling me that we weren’t young any more; that I wasn’t dressing appropriately; that it was time I grew up,’ she says.

‘Now I’m free to live the life I wanted to lead. And I do feel younger.’

The toyboy doesn’t come without risk, however. The irony, of course, is that while older women sometimes pick these men to make them look younger, there’s nothing more ageing than standing next to someone many years your junior. However well preserved she might be, there’s the danger that someone might mistake her as the mother, rather than the lover.

But there are other good reasons for older women to seek sex and love with younger men, according to Jo Hemmings — most pertinently the fact that there’s a shortage of men of a certain age.

Director Sam Taylor, 42, met toyboy Aaron Johnson when he was just 19, on the set of her film Nowhere Boy

‘If you’re 45, witty and attractive, and looking for a man with similar qualities, you might find that they’re all snapped up,’ she says.

‘But in the world of online dating, you’ll meet plenty of younger guys who know that older women have a lot going for them. Women who have had their families and who come across as wise, mature and sexy without being needy or wanting a baby.’

For a generation of commitment-shy men, who feel they’re being sized up as potential fathers on the second date by the hordes of childless 30-somethings fixated on their biological clock, an older woman is often seen as an enticing alternative.

The same holds true for women in their 50s or 60s who are looking for love after divorce and decades of bringing up a family — juggling work with children and finances.

Finally, it’s all about them again, says Hemmings. Perhaps for the first time since their 20s, hedonism is top of the agenda.

Indeed, it’s often the case that with middle age, in comes the younger lover and out goes conventional modes of romance.

It’s this ease in yourself and willingness to live outside establishment norms, which is so appealing to the toyboy — something with which Stephen Vizinczey, author of In Praise Of Older Women, agrees.

His 1965 fictional autobiography about a young philosopher who was beguiled by older girlfriends sold seven million copies.

Older women, says Vizinczey, are more relaxed and less self- conscious. ‘You know your body better, so it makes sense that you’re sexier.’

Occasionally, experimenting with a toyboy can turn into real love, as Sam Taylor Wood, director of Fifty Shades Of Grey, can attest.

After being branded a cougar at the age of 42 for getting together with actor Aaron Johnson, aged just 19 when she met him on the set of her film Nowhere Boy, Taylor Wood, hit back.

‘The number of men I know with the same age gap that we have . . . how come no one says anything about that. It’s totally sexist,’ she said.

Seven years and two children later, the couple are still confounding the naysayers.

Aaron Johnson, though, is a rare beast. It’s more likely that a toyboy will be a bit of fun at best, or an expensive humiliation at worst.

There’s always the risk that you may get cast off for a younger model, and end up feeling like an old fool.

But given that husbands the same age as you are just as likely to do the same thing, you might be inclined, like Madonna, to keep your (younger) options open.

After all, a newly invigorated, middle-aged woman has a cachet today like never before. She’s rebooting her sexuality — with a little help from her toyboy.