Consider Mick Jagger. A decade ago, when Mick was 57, we openly wondered how much longer he could keep it up. A pop star? In his fifties? It just wasn't rock'n'roll. In 2011, however, the question itself seems strangely dated. Age has merely added patina to the ineffable cool of the Rolling Stones, and these days nobody is calling for Jagger's retirement. With a birthday placing him at the very forefront of the "Baby Boomer" cohort, Mick is also in the vanguard of a redefinition of our experiences and perceptions of ageing.
For, while fear of old age has created a ready market of paranoid consumers for "anti-ageing" products, and those over 40, particularly women, continue to feel discriminated against, if Jagger is anything to go by, perhaps the very generation that invented the cult of youth might also be the cohort to debunk it – especially given that, according to demographers, half of us will be over 50 by 2020.
The term "Alpha Boomer" was recently coined in the US to describe 55- to 64-year-olds, currently the fastest-growing demographic in that nation. Alpha Boomers enjoy America's second-highest median income, spend more money on goods and services and own more iPads and smartphones than any other age group. Over here, too, according to research carried out by ad agency Beta, "the 50-plus market will soon be the biggest, richest and most influential in the UK".
More to the point, these are the very guys and gals who rejected "intergenerational solidarity within class", according to sociologist of ageing Dr Chris Gilleard, in favour of "an alliance with others of their age group". As the post-war generation hits their fifties and sixties, they may have left behind their chronological youth, but they've carried within them a culture, says Gilleard, of "alertness, vitality and authenticity". If the Alpha Boomers have anything to do with it, ageing will never be the same again.
I can't quite claim to be a true Boomer – I was born in 1967 – but with 50 edging ever closer, I'm fascinated by the trail they're blazing. As life expectancy increases to 100 and health and wellbeing in later life improves, 50 can justly be considered the start of a "second half" in the game of life, which is likely to be as enthralling and decisive as the first.
That shift gives rather a different complexion to the phrase "mid-life crisis", which was coined to describe the tragic flailings of those who fear not just that the first and best part of life is gone, but also that all the important decisions, peak experiences, emotional highs and sexual thrills are also over. Men and women in the grip of mid-life crises are in denial, or so it was said, about their own mortality, something no Harley-Davidson or decree absolute can avert.
I've been accused of something similar; in the four years since I hit 40 I have left my marriage, fallen in love with a younger man, quit drinking, started writing a novel, done Glastonbury for the first time, got the boob job I always promised myself, gone into therapy and begun to learn how to enjoy my own company. I also know how to check the oil in my car. You might call all that upheaval, some of it intensely painful for everyone concerned, a crisis; I call it a recognition that life is short, and that 40 is not too late to fix the stuff that isn't working. And yes, I buy clothes at Topshop and H&M, go to clubs and gigs, share clothes with my daughter, am fitter than I was at 24 and occasionally entertain myself working my very best Milf look.
Ironically, I now feel younger than I did at 37, when, pregnant with my second child, I remember confiding to a friend my fears that I would never get back into the job market after the birth because I would be "nearly 40". I think I regarded the arrival of my grandchildren as the next truly momentous event in an existence that had served its reproductive purpose – an idea almost as laughable as the one I vividly remember having at 24, that I was much too grown-up, sensible and frankly square to get wasted on E and whizz in a muddy field somewhere. Talk about age apartheid.
My point is that I'm no longer inclined to rule out interests, activities or experiences because it is "too late" or they seem "age-inappropriate". Nor do I regard it as a catastrophe that my life hasn't followed the simple linearity of career, marriage, kids and retirement. In that sense I have a lot k in common with the fiftysomethings targeted by a new website called High50 (pronounce it like Hawaii 5-0). The brainchild of Beta founder Robert Campbell, the site was launched to meet the needs and interests of what he identified as a new breed of 50- to 65-year-olds (one telling stat reveals that they are the fastest-growing demographic on Facebook and Twitter). "It used to be the case that you had one career, one wife and one family and you retired to the seaside at 65," says Campbell. "But we are now living and working so much longer that 50 has become an opportunity for major life change. People come out as gay, or get divorced. They become inner- rather than outer-directed; post-50, you do what you want to do, not what other people want you to do."
A "sexy, cool, interesting and relevant" alternative for fiftysomethings who couldn't care about cruises or life insurance, High50 is edited by Tim Willis, 52, who describes himself thus: "I hope I've grown up without growing old. Essentially, I'm still the person I was 20 years ago: style still matters to me as much as content; I haven't given up on life or laughter. In fact, I'm as free as I was when I left university. Being fiftysomething is like being a teenager, with experience."
In her new book Amortality: the Pleasures and Perils of Living Agelessly, Catherine Mayer cleverly analyses "the swelling ranks of people who live agelessly, doing and consuming many of the same things from teens to old age... we never consider ourselves too young to pair up, break up, launch businesses, take on the world; or too old for fresh commitments, the latest technologies or new diversions".
Alpha Boomers would certainly recognise the pleasures of "amortality", but there's an important sense in which being over 50 also offers new and different freedoms. Theorists of ageing have long posited the idea of the Third Age (the phrase was invented by University of the Third Age co-founder Peter Laslett), the idea being that modern medicine has opened up a window of opportunity between retirement and terminal infirmity hitherto unknown. For the writer and former clinical scientist Raymond Tallis, an extension of life beyond the basic storyline (mature, reproduce, perish) is also a chance to "redefine what it means to be human". "One can look beyond economic survival and child-rearing to ask some fundamental questions about the meaning of life. And older people can speak freely, because they don't have to answer to authority. In a sense, we have picked up the baton of rebellion from the young."
The New Age thinker Deepak Chopra touches on something similar when he describes our "second life" post-50 as a time when we'll want to focus on "quality of life and spiritual growth". After all, he continues, "There's only so much juice you can extract from getting and spending, working and consuming, entertaining yourself and socialising."
Of course, for many Alpha Boomers, retirement is neither possible nor desirable. (That's another cultural shift; remember back when the dream of every thrusting young banker was to make enough money to retire at 45? Now the question would be: retire to do what?) Continued, vigorous engagement with the world, albeit on one's own terms, is an Alpha Boomer sine qua non. It's hard to imagine George Clooney, Vivienne Westwood, Martin Amis, Lynne Franks, James Dyson, Kate Bush or Nick Cave taking a back seat to let the young people get on with it.
Yet "vigorous engagement" is easier said than done if you've been made redundant at 50, or you feel "invisible" in the street or workplace. Our 50-plus lives have the potential to be exciting and rewarding, yes, but they can also be financially and personally difficult. For all the excitement among marketers who have finally noticed a vast untapped demographic of hip, monied consumers, Boomers "have faced significant economic and lifestyle challenges, particularly in the aftermath of the 2007-2009 recession", points out a report prepared by marketing trade magazine Ad Age. "As they've been edged out of the workforce or seen retirement savings dwindle, some have found they are unable to assume a brighter future, unlike younger generations who have time to make up for losses. For those born between 1955 and 1964, many of whom are taking care of children and older parents, the last few years have been particularly challenging."
Robert Campbell suggests that over-fifties who have been treated as "expendable" by their corporation should consider working for themselves: "Statistically, businesses started by entrepreneurs in their fifties have a greater chance of success than those launched by people in their thirties." In 2010, around 16 per cent of those claiming unemployment benefit were 50 and over, and Campbell is calling for mentoring, entrepreneurs' clubs and even work placements to address their needs. The Prince's Initiative for Mature Enterprise, set up by the Prince of Wales, is currently the only national UK charity that helps the over-fifties get back into work through self-employment
Initiatives such as these won't help those who feel cast on the scrapheap of life, however. In New York, Barbara Grufferman's book The Best of Everything After 50, published in 2010, tapped into a wellspring of misery among women who felt that, at 50, frumpy irrelevance beckoned. Grufferman wrote it after she turned 50, hit the menopause and was "overwhelmed by the many media messages shouting at me from all sides that younger is better, sexier, more desirable, and that older is another word for invisible.
"If you're feeling invisible, maybe it's because you're retreating," adds Grufferman. "My message to women is, whatever your age, embrace it. Don't try to look younger, just be the best you can at your age."
In the UK, Ceri Wheeldon is doing something similar with her website and social network fabafterfifty.com. "As I approached 50 myself," she says, "I was appalled at the ageism I could see around me, so I decided to try to change attitudes. Far from being ready to sit in a rocking chair and knit, today's over-fifties are reinventing themselves, setting up new businesses and having second careers." In yet another sign of the times, the new Mumsnet off-shoot Gransnet, edited by Geraldine Bedell, namechecks Banksy, moon cups, digital photography and the Nintendo DSi XL on its homepage, while the tone of forums so far, according to Bedell, is "buoyant and upbeat, not grumpy old git".
According to Emma Soames, Saga's former editor and now editor-at-large, women do now "go on feeling sexy for longer" – and furthermore, "People who work in the creative industries get better with age." Soames directs me to the runaway French bestseller The Warmth of the Heart Prevents Your Body from Rusting: Ageing Without Growing Old, by the psychologist Marie de Hennezel, which urges us to embrace our "golden age". "We have to kiss goodbye to our young skin and accept our wrinkles, but another kind of beauty is accessible to us – that of emotional youth," argues De Hennezel.
With so many cool, desirable, interesting, engagé and powerful men and women over 50 out there, I've begun to wonder whether I should update the profile on my Facebook page. If I really believe ageism is shortly to go the way of sexism, racism, homophobia and other low-rent prejudices shunned by polite society, surely I should include not just the day and month, but also the year of my birth, which, like a number of other Facebook users d'une certaine age, I'd reasoned was for me to know and others to wonder about. Will I choose to be out and proud, or should I retain what's left of my mystique? Oh, even better. I can choose a third, genius option, perfectly in tune with the zeitgeist: "Don't show my birthday in my profile." If age is just a number, the precise figure is surely entirely beside the point.
Christyne Remnant, 66 is married to a property developer and has three children, aged 42, 40 and 23, and two grandchildren. She started modelling in local fashion shows when she was 63; her most recent appearance was on the Oxford Fashion Week catwalk
I got involved in the local "beauty circuit" when I saw an ad in the Southern Daily Echo inviting readers to submit photos to enter a competition for a catwalk show with Southampton FC. I sent in my daughter's photo then, just for fun, added my own. I was amazed to get down to the final 12, even though the other entrants were in their teens and twenties. I've always looked younger than my age; when I had my youngest daughter, at 43, the other mothers all assumed I was the same age as them.
I think it comes down to positive thinking and good genes. I like to laugh and have fun, but I don't exercise at all; I've tried belly dancing and salsa dancing but I find it boring. I'm lucky in that I like the right foods, and my rather oily skin has stood me in good stead. I've never gone in for facials or any of that pampering – though the one thing I am very conscious about is sun protection.
I put my youthfulness down to personality; I think people find me quite entertaining. I'd hate to be thought of as full of myself, but if something looks fun, I'll always give it a go. It's also a chance to meet new people.
Last year my husband and I went on holiday and made friends with another couple. On the last night the chap took to me to one side and said, "You're the woman I've been waiting for all my life." When I told him how old I was, he shrugged and said, "Nobody's perfect." So I suppose at the moment I'm still hanging on in there.
The Hon Valentine Guinness, 52, is a member of the New Forbidden, a band reformed from Loyd Grossman's original 1970s line-up Jet Bronx and the Forbidden. The band are scheduled to play at Glastonbury, Vintage at Goodwood and Guilfest this summer. He is divorced, with two teenage daughters
I had already retired from the music business twice when Loyd told me he'd been invited to make a cameo appearance at a punk festival in Blackpool called Rebellion. That was in 2007. I'd released some singles with two bands, Panic and later Darling, in the 1980s and 1990s, but when I hit 40 I had to decide whether I still wanted to be doing the pub circuit at my age. It just seemed inappropriate. I dropped out of music and started writing plays – one got put on at the Jermyn Street Theatre and got pretty good reviews. When Loyd told me about Rebellion, however, I suggested we play a proper set and it got us writing songs again.
Our major break was meeting the record producer Geoff Haslam, who's worked with Aretha Franklin and the Velvet Underground. He really liked our stuff, which you could describe as fast, catchy guitar rock, and we recorded our new album, Ain't Doin' Nothin', for his label, Gas Records. It's not really music for middle-aged people; in fact, all my 19-year-old daughter's friends are mad about the band. There has definitely been a change in attitude about age. Twenty years ago, you'd get funny looks if you went into a pub as a band of fiftysomethings. Now we play on the same bill as twentysomethings and there's a mutual admiration. My daughter and her friends listen to everything from Elvis to the Black Eyed Peas. They're far less judgemental than we were.
To buy 'Ain't Doin' Nothin' and for full gig listings, visit thenewforbidden.com
Age shall not wither them: The Alpha celebrities
Nicky Haslam, 71
Interior designer Haslam is also a cabaret singer, art editor, book reviewer, memoirist, not to mention well-connected and much-snapped socialite, all in his spare time. He's also known for embracing new technology: he blogs for his own website, nh-design.co.uk, and telegraph.co.uk.
John Lydon, 55
Though best known for epitomising the anarchic spirit of the Sex Pistols, Lydon, aka Johnny Rotten, has refused to grow old gracefully. He brushed off accusations of selling out when he advertised Country Life butter and embraced reality TV with a stint on I'm a Celebrity... He also continues to tour with his band PiL, with the promise of a new album this year.
Simon Le Bon, 52
Le Bon still fronts Duran Duran; their latest album was produced by Mark Ronson, and a show on their tour was directed by David Lynch. Despite nearly dying in a yacht race in 1985, Le Bon continues to sail. He's a regular tweeter, and his wife, Yasmin, is also a prime Alpha Boomer: she's been a model for nearly 30 years and has no plans to retire.
Jerry Hall, 54
She found fame as a model and rock star's wife, but Jerry Hall has continued to work as the years roll by, stripping off for The Graduate and Calendar Girls on stage, acting in a recent TV adaptation of Martin Amis's Money, and modelling for Chanel. She's also a vocal defender of growing old naturally, rejecting Botox and surgery as unnatural.
Vivienne Westwood, 70
Neither the fashion doyenne's punk attitude nor her work ethic has diminished, as she continues to produce popular collections. She's also remained loud and proud when it comes to voicing her political opinions, and has become a strident climate-change campaigner.
Kim Cattrall, 54
Best known for playing Sex and the City's Samantha, a woman who certainly didn't let hitting 50 slow her down, there's more to Cattrall than Cosmopolitans and cavorting: fêted for recent performances on the British stage, in Private Lives and Antony and Cleopatra, as well as Roman Polanski's film The Ghost, she has also spoken out against plastic surgery and ageism in Hollywood. Holly Williams