The third-agers

The oldies are coming. By 2020, more than half of all British adults will be over 50. In a society that celebrates smooth skin, taut muscles and children's-television-presenter levels of energy, and whose main hope of future economic success is said to lie in creativity and innovation, we will be getting greyer, wrinklier and slower. For the first time in history, most of us can expect to get old.

So what can we look forward to, apart from lots of cheap motor insurance? It's hard to know, because there's so little discussion. Despite the hordes heading for old age, we prefer to maintain a state of collective denial. Public survival and private self-esteem depend on an Anne Robinson facelifted-type refusal to acknowledge our age. And this is not so surprising when media coverage of ageing invariably focuses on problems of one sort or another: Alzheimer's, or the economic threat posed by an ageing population, with the clear implication that such a population is no use to anyone.

In fact, the over-50s own 80 per cent of the nation's wealth. They include students, newlyweds, parents of young children, chief executives, government ministers, marathon -runners, backpackers. If we define the old as they have been defined throughout history, as those aged between 50 and 100-plus, they cover two to three generations and include many of the most eminent, active and affluent people in the country.

Even if we put the age limit higher, given levels of fitness, the same is still true. In the 20th century, notes Pat Thane, professor of contemporary history at London University: 'For most people, death was not preceded by a long period of serious dependency.'

'Fifty is the new 30,' claims Andrew Goodsell, chief executive of Saga, even more bullishly. Saga has built up a £530 million-turnover business from specialising in services (travel, insurance, publishing) for the over-50s. It has done so by neatly finessing the paradox of being an age-related enterprise whose premise is that people don't want to be defined by age. 'We don't like generalised tags,' Goodsell explains. 'We don't think it's appropriate to categorise people.'

Despite the ironies of the sell, he is right. A thriving third age, as the French usefully think of it, is not primarily dependent on the number of birthdays passed. People can become decrepit fourth-agers in their sixties, or they can be like Jenny Wood-Allen of Dundee who, in 2002, at the age of 90, became the oldest woman to complete a marathon. This makes George Bush Snr's decision to celebrate his 80th birthday by making a parachute jump look almost half-hearted.

The multitude of third-agers may be new, but, as Pat Thane points out in a new book, The Long History of Old Age,(Thames and Hudson), longevity itself is not. Before the 20th century, life expectancy was only 40-45, but the figures were skewed by high rates of infant and maternal mortality. In the 18th century, at least 10 per cent of the European population was over 60.

A good proportion of these older people have always refused to settle down in front of the historical equivalent of Countdown. Doge Enrico -Dandolo led the citizens of Venice on the fourth Crusade in 1204 at the age of 97. John Wesley eventually admitted to starting to feel old in 1789 at 86. Victor Hugo became a senator in 1876 aged 74. Mid-20th-century politics simply wouldn't have existed without old men (which might, in fact, have been a good thing): Stalin died in office at 74, Brezhnev at 76. Winston Churchill was 65 when the Second World War broke out in 1939, endured a punishing workload as war leader for the next six years and was re-elected Prime Minister in 1951 aged nearly 77. Franco was head of state in Spain until he died at 83 in 1975.

Health, clearly, is the single most important ingredient of a good old age. The US National Centre for Chronic Disease Prevention claims that research now unequivocally proves that lifestyle is more influential than genes in avoiding age-related health collapse. If this seems alarming, it may be comforting to know that experts have always prescribed diets for a healthy future, and they have been many and various. In the 17th century, for instance, older people were supposed to drink red wine and milk and eat the flesh of young animals, presumably on the grounds that these foods had something vaguely virile about them.

All the vibrant older people I talked to for this article were, however, at least conscious of diet and exercise. Margery Mason, a 92-year-old working actor who has recently written her memoirs, had just swum half a mile when I went to see her at her garden flat in Swiss Cottage in north London. She does this every weekday, except on her recent birthday, when she swam a mile by way of celebration. She got her diving certificate the day after her 81st birthday but recently gave up, fed up with how protective people had become of her.

Affluence is important if you want to spend winters in the sun or climb Kilimanjaro, but above a certain level of comfort, it matters less than one might expect. Hugh Scurlock, 64, of Matlock in Derbyshire, is living on part of a teacher's pension, following the break-up of his 31-year marriage when he w as 53. Despite having had a hip replacement, he is a triathlete and in training for an iron man competition next year (a two-and-a-half mile swim, followed by a 112-mile cycle ride, followed by a marathon) and recently went backpacking up the Amazon. He has remarried and is writing his memoirs. 'Money's not that important,' he says. 'What you really need is goals.'

Intense loneliness in old age is less common than it used to be. Lower infant mortality rates mean that people are now commonly in touch with at least one child. Moving around for work or marriage is nothing new, but the telephone and internet make keeping in touch much simpler. Communities are no longer constrained by geography but may be interest-based, including those of ethnicity and religion. Family and community clearly sustain many third-agers, but they are not what really seems to single out the happiest and most vigorous.

Cicero said: 'Old age will only be respected if it fights for itself, maintains its rights, avoids dependence on anyone and asserts control over its own to its last breath.' This remains as true for the 21st-century third-agers as it was for the Romans. What you notice about the most vital third-agers is the depth of their passions, the scope of their projects.

Almost every week, someone issues a dire warning about the demographic time bomb. This month, the OECD predicted a 30 per cent decline in global economic growth as a result of too few babies and an army of oldsters on the march towards their centenaries. Such predictions usually ignore the effects of immigration and the cost 'benefits' of having to educate fewer children. Every bit as importantly, they fail to acknowledge the possibility that not everyone will want to retire at 65.

People who do creative jobs tend to want to go on doing them for as long as possible, because the creativity is mainly what makes them feel human. In the past few years, Margery Mason has had small parts in Love Actually and the latest Harry Potter, done a couple of television roles and been on stage in Three Sisters with Kristin Scott Thomas directed by Michael Blakemore. But to her great disappointment, she's had nothing of the longevity or impact of her part in Peak Practice, in which she began an eight-year run at the age of 79.

She doesn't have a pension: 'Not even a proper state pension, because when I was out of work, I didn't always bother to sign on.' But this is not what drives her. (She owns two floors of a beautiful house with garden, which must be worth around a million.) Nor, despite having done some 'very, very good work in my time', did she ever quite break through. But she doesn't mind this. She continues because she simply can't imagine doing anything else; acting remains who she is. Her main complaint about life now she's old? 'I'm very sad and concerned about not apparently having any work in the offing. That, and being called "dear" by taxi drivers.'

Union lobbying recently blocked the government's plans to raise the normal retirement age of public servants from 60 to 65. For many people, this will have been cause for celebration: retirement is the first time in their lives they can devote themselves to things that really interest them. But it's not axiomatic that everyone wants to stop working as soon as possible.

Sohan Singh qualified to work in the probation service at the age of 50 and finished his master's in criminology with the Open University last year. A former representative of Kenya in the Mr Universe competition, and a karate black belt third dan, he works out every day. Last year, when he reached 65, he was told he had to retire.

'I loved the job and didn't really understand how you can be fit to do it one day and not the next. If you've got a contribution to make to society, why would you want to sit back and say, OK, now I am 65, I will stop?' He is currently running a successful project to introduce schoolchildren to a range of faiths in an area of Sunderland where there are high levels of BNP activity.

Having sat on the executive of the regional Racial Equality Council for 14 years and been its chair, he speaks with some authority when he says: 'Ageism is worse than racism or sexism, because there is so little recognition that it is wrong. There is no commission fighting for your rights ... I'm still physically fit and mentally agile; I don't want to put my feet up yet.

'Ageing is a little bit like disability, in that a lot of the problems are socially created. People may have slightly more or different needs as they get older, but the key thing is to keep people as human beings, functioning as fully as possible. It is society that imposes on you a sense that you are old. I feel pretty young.'

Older workers are commonly thought to be less adaptable, less capable of learning, less creative and less adept at mastering technology. Yet whenever these assumptions have been tested, they have been found to be wrong. Age, as Terry Wogan once said, only matters if you're a cheese.

The one thing you can say about older people is that there's no one thing you can say about them. They're a vast and heterogeneous group, which is why nomenclature has proved so difficult: can't call them pensioners any more, or OAPs, or the elderly unless they're in a care home. The American term 'seniors' looked promising for a while but may well now be permanently contaminated by the phrase: 'I'm having a senior moment.'

Far from struggling to remember where they put the keys, many in this group are exhaustingly dynamic. I lost count of how many over-60s I came across who were cycling the length and breadth of Britain for charity, or sleeping in Buenos Aires guesthouses so as to learn to salsa properly. Future historians are going to be overwhelmed by material, because every other person seems to be writing a memoir, not necessarily for publication, but because, for the first time in history, masses of -people have enough time, energy and education to try it.

Margery Mason told me she had the most satisfying love affair of her life when she was in her 60s. She's probably not the only one. Perhaps we need to go back to something more like the Middle Ages, when a person's precise age wasn't always known, when society was less bureaucratised and age wasn't a basic organising principle. There will come a time for each of us when we can no longer do what we want. Until then, it makes sense to get on and do as much as you can.