Dance to the music of time

A study of worms suggests we could live 50 more years. Blake Morrison sees misery ahead

Round about three this afternoon, at her house in Yorkshire, we'll drink champagne in celebration of my mother, whose 80th birthday it is today. There'll be 30 or 40 of us, friends and relations, and of course my mother herself, wheeled across from the nearby nursing home where she has spent the past few weeks. Inevitably, we'll be thinking of absent guests - those, like my father, who're no longer here to be invited, or those too ill to make the journey. Still, the mood will be festive: we're here to mark an important milestone.

My mother counts herself lucky to have reached 80. Her own parents died young, before she was 30. And of her nine brothers and sisters, born in County Kerry between 1910 and 1920, all are dead now - except one, who has Alzheimer's. As a child, growing up where and when she did, my mother could never have expected to reach this age, or to have her wits about her if she did.

Yet hers is a fairly typical case - in line with the national average. Fewer than a fifth of women born in 1845 reached the age of 75, whereas 57 per cent of women born in 1921 were still alive last year. In the past 20 years, the average life expectancy at birth for men and women has risen by four years, to 73 and 79 respectively. Most extraordinary of all, the number of centenarians in Britain is rising at a rate of 7 per cent each year: in 1911, there were only 128 out of a population of 36 million; in 1951, still only 300; but in 1991, there were 4,400, and the projected figure for 2031 is 45,000.

The dream of extending the human span is older than Methuselah (who lived, says the Bible, to be 969). So these figures, culled from the splendidly comprehensive two- volume survey "The Health of Adult Britain, 1841-1944", published by the Office for National Statistics last week, are cause for satisfaction. Cleaner air and water, improved housing conditions, wider immunisation programmes, reduction in tobacco and alcohol addiction - all these have helped. Aids and influenza aside, infectious diseases no longer threaten us. Medical and scientific advances, especially in the area of cancer and heart disease, promise steady, perhaps even spectacular improvement of life expectancy in the years ahead.

But does our living longer also mean we're becoming healthier? Ah, there's the catch. Last week's survey doesn't suggest that an increase in life expectancy has been accompanied by the expectancy of an extra few years of health. On the contrary, there is evidence to suggest that, should they reach 65, men and women will begin to deteriorate much as before, in their early seventies. Death is being postponed, but the period of ill-health preceding it is the same as or longer than before. "Compression of mortality" (ie, when death comes to the vast majority between the ages of 65 and 85) hasn't been accompanied by "Compression of morbidity" (everyone enjoying good health until a last, brief implosion of bad). In short, the elderly, and women especially, can expect to spend a number of years in a condition that will at best be unhealthy and uncomfortable, and at worst immobile, incontinent and infirm.

No one likes to admit this. In our health-driven culture, fitness, diet and exercise are the holy trinity, and the gym is a temple - whereas the hospital is as shameful an institution as the workhouse was to Victorians, the place to which we go to confess failure. Senescence - "reduced physiological adaptability" - has become a dirty secret. Each death has to be ascribed a specific cause, as if it were an accident that might have been avoided, not the inevitable outcome (as many deaths are) of the rusting up and wearing out of the human body. With luck, the young need never visit the unhealthy old, or even know they exist: many of them live behind closed doors and hospital screens, out of sight.

If the cult of youth makes us reluctant to admit the bitter truths of old age, so does the cult of age. Growing old, so countless memoirs and polemics tell us, is a positive experience: with grey hair comes the getting of wisdom, freedom, independence, irresponsibility. The Third Age is a fully fledged political movement now, whose members rightly argue that pensioners are badly treated and discriminated against, and that their usefulness has been devalued.

The Third Agers deserve every support: more power to their wrinkly elbow. But their philosophy tends to obscure the truth about the Fourth Age ahead of them, which isn't quite so attractive a phase of life. The point is well illustrated in Samuel Johnson's Rasselas, when the young prince meets an old man whose sagacity he envies. Young fool, he's told, such envy is misplaced. If you live to be old, all pleasure and hope of future disappear - even the consolations of friendship do, since many friends will predecease you. The moral: "It is enough that age can obtain ease."

The worry now is that by searching to prolong life for its own sake, ("French woman celebrates 121st birthday!"), we forget the ease of kindly fatal illnesses like pneumonia, and the easefulness of death itself. Increasingly, the aspiration of researchers in gerontology isn't the humdrum task of relieving pain and discomfort but finding the master-key for extending the human span. At the University of California, as Malcolm Gladwell reported in an excellent article in the New Yorker last year, Professor Michael Rose has created a superbreed of fruit flies: they live for 120 days, rather than the usual 60. Elsewhere in the US, in a lab on Long Island, work is being carried out on "telomeres", which some scientists believe are the timing devices that regulate the ageing of cells. Yet another team has identified such a gene - which they call Age-1 - in earthworms: worms with a certain mutation in the gene lived 65 per cent longer; carry this over to the human sphere, and the flame of life could burn an extra 40 or 50 years.

But would it be worth the candle? What would our quality of life be like? In Gulliver's Travels, the eponymous hero, after his travels to Lilliput and Brobdingnag, reaches the island of Luggnagg, where he is told of a race of immortals, called Struldbruggs. Highly excited at first - "happy people who enjoy so many examples of ancient virtue!" - he learns to his dismay that by the time they are 80 the Struldbruggs "had not only all the follies and infirmities of old men, but many more which arose from the dreadful prospect of never dying". Morose, senile and "dead to all natural affections", they are also ugly and deformed - "the most mortifying sight I ever beheld".

This is like the fable of a man granted his wish for eternal life, only to find that it's a perpetuity not of youth but age. Anyone who thinks Swift's parable too savage for our more civilised age should read Joan Brady's Death Comes For Peter Pan, a novel which documents the abuses and corruption of the Medicare system in the US, and the dodgy practices of various hospitals and nursing homes. The condition of the patients she describes is appalling. There's no doubt they'd be better off dead.

Few of us, in health, would pass up the chance to live an extra 20 years. If every phase of life could be doubled (10 more years of being a child! an extra decade of adolescence!), we might even accept our old age being twice as long, too. But a decade or more of pain, indignity and disability, with only death at the end of it: where's the point in that? The dread is that we'll create a system (perhaps already have) where people are kept alive who, if they weren't too sick to speak or understand, would choose to be allowed to die.

"O! Let him pass," says Kent of the dying Lear, "he hates him/That would upon the rack of this tough world/Stretch him out longer." My mother, who has watched her health deteriorate over the past three months, uses a different language. So long as she has quality of life, she wants to be here; once it goes, she hopes she'll go, too. It's the heartbreaking common sense of an octogenarian. I'll be thinking of it as we toast her health today.