Who wants to live to 130?

Prehistoric man had an average lifespan of about 19 years. Mind you, 19 years of prehistory probably felt a whole lot longer. Scientists are now telling us that within a decade or so human beings will be living seven or eight times as long as prehistoric man, between 40 and 50 years longer than we do now. One hundred and thirty years will be the average lifetime for women, a little less for men. That's what men get for wasting time the way they have always tended to do, I guess: time, it seems, will continue to waste them back.

Researchers of our proposed longevity are basing their studies on a peculiarly tough variety of earthworm, and there is justice in that, too. We haven't been very nice to worms over the centuries: small boys impale them on hooks to lure fish, and no less cosmic a voice than Shakespeare called them not simply vile, but "vilest worms". It's good news for worms, and only fair, that science has redeemed them from their sinister metaphorical role and their strictly carrion function. Worms live here too, right? And a worm's gotta chew what a worm's gotta chew.

How, I wonder, do we intend to fill the many extra years science promises us? If people around 80 or so, still in their prime, take voluntary retirement, what are they going to do with all the long, long days they'll have left to live? Gardens and bridge won't keep them happy for long. Even writing memoirs can't be much fun when recollection starts lasting three times as long as action.

Will gangs of disaffected octogenarians hang around the mean streets, looking for trouble? Then again, if the fit, spry aged of the future, still equipped with all their marbles, refuse to retire, what work will be left for energetic striplings of 45 and 50, most of them with higher degrees in sociology?

And imagine what a lot of new generation gaps will open up in one long lifetime. Centenarians signing petitions and grumbling to the authorities about those 60-year-old hippie-types who have moved in down the street with their 50-year-old good-time girls and that racket they call music. As for genuine children - kids of 20 or 30 - to what lengths will they have to go to express natural rebellion in a world packed to bursting with the chronologically old? Suicide is bound to become stylish among the young, or addiction to virtual reality rather than the real thing. How else can they be seen to throw away what is apparently of supreme value to preceding generations? Time, I mean, for its own sake.

Apparently the fabulous worms don't just live a long time, they also stay good-looking right up to the end. Thus, it could happen at last, that in a world where everybody looks young for ever, plastic surgeons will have to devise new techniques to make taut faces fall; expensive wrinkle creams will promise to create interesting folds and bags practically overnight; and there will be a vogue for false liver spots to give hands that enviably exotic patina for evenings. What else can fashion do when youth is cheap, except turn to crumblies and wrinklies for glamour? Women who are merely 70 won't look a day under 83, and when asked their age they'll bat their lashless lids and swear they're pushing 90.

Granted, youth does seem to stretch itself into a roughly steady proportion of life expectancy, and it has been lasting longer and longer over recent generations. But to be honest, what is youth all that good for? When you get right down to it, practically nothing, except sex.

I haven't heard whether or not the amazing worm stays sexy. God, I hope not. One of the benefits of ageing as we do it now is the opportunity to outgrow lust. The thought is appalling of seven or eight decades of unrelenting juiciness with all the junk it pulls along - disappointment, ennui, perversion, infidelity, jealousy, insecurity, STDs, unwanted pregnancy. Damn those worms. If they stay sexy into their decades, who needs them?

I'm not saying an additional few years wouldn't be pleasant; enough time to sort out all the old snapshots and clean the cupboard under the stairs. But why, I wonder, do we think we want to live as long as the eternal worm? One hundred and thirty years or so seems a hell of a long time to have to go on holding opinions, supporting charities, raising babies, keeping our spirits up, while incidentally bankrupting society for our pensions.

I don't know how the worms manage things, but we human critters have a limited attention span: it's part of our charm. There is nothing we can't get fed up with in due course, not sex, not art, not our own company; and I wonder if it takes as long as we imagine to have enough of life itself?

Miles Kington is on holiday.