Miller Quarles is just your average Texan millionaire in cowboy boots. Except that he plans to live forever
"Of course I'm desperate," admits Miller Quarles, washing down his lettuce leaves with a glass of mineral water and a cocktail of pharmaceuticals. "After all, I have a 50 per cent chance of living another 200 years. Wouldn't you want to make it a sure thing?"

Quarles may sound crazy, but he believes he has insider knowledge that eternal life is within his grasp. Five years ago he set in train research into the human biological clock and received proof, he says, that not only could it be made to stop, it could be made to tick backwards.

The implications are fabulous for our sex lives, says the 81-year-old millionaire: think of the possibilities for cavorting when everyone is brimming with youthful vigour, no one looks older than 40 and conception has been made as preventable as smallpox.

This is just the kind of talk you expect from a Texan - and Quarles fits the stereotype. He walks tall in his Stetson and cowboy boots, and his blue eyes twinkle with a boyishness accentuated by a brushed-forward preppy hairstyle; he doesn't even look old until he sits close enough for you to see that his face is lined and weathered, with the texture of parchment.

Quarles is driven by a determination to grab life by the throat and hold on to it forever. He has done the hard part - finding a scientist with the recipe for eternal life - and it is his tragedy that the project went on the back burner when research threw up a potential cancer cure.

Persuading cells to keep dividing is the secret of immortality. There is a turnover of cells in the body. Red blood cells, for example, last only for about 40 days before being broken down and removed. They are replenished by "stem cells" in the bone marrow. Cell division, the process whereby one cell splits to form two progeny cells, is essential to the continuance of life.

Quarles says that his pet scientist, Dr Mike West, discovered how to make human cells keep dividing several years ago. But en route, he became more interested in discovering how to stop cancer cells dividing and shifted the thrust of his research, which was great news for cancer sufferers, but bad news for oldies desperate to be rescued from death by ageing.

So Quarles has to keep going until the scientists get back to trying to produce the elixir of youth, or until he can raise enough money to persuade them to do so. Which explains the lettuce leaves, the water and the army of pills.

"I can't afford to abuse my body like all the people committing suicide around me," he explains, shuffling out as many vitamins, minerals and enzymes as he can swallow at a single sitting. They won't even be around to benefit from the cure for old age.

"I have to stay alive and keep healthy, because statistically time is running out. I don't smoke, I hardly drink - maybe a glass of wine a month - I eat very little, mainly vegetables and a little chicken, and I'm rigorous about my supplements. I take 8000mg of vitamin C daily, Beta-Carotene, vitamin E, Melatonin, L-lysine, which has the potential to prolong lifespan by eight years, and the cancer preventative Co-enzyme Q10." Add to this regime his daily karate workout and competition tennis - Quarles holds Houston's over-80s title - and he seems justified in pronouncing himself "exceptional for an 81-year-old".

Quarles is a founder of Geron, a Silicon Valley corporation that leads the field in cell biology. Geron is headed by Dr West, the cell biologist Quarles endowed with seed money, who by 1992 was demonstrating the secret of immortality on television. "We can literally shift cells between an ageing and immortal state, back and forth," Dr West enthused, reporting on his successful manipulation of the brain cells of a 92-year-old woman.

When he began working on a cancer treatment, Dr West found investors throwing money at him. Seventy-two million dollars of venture capital has now built up behind him, and with $30m in licensing fees for a cancer drug on the table, Quarles can understand why Geron sidelined his immortality project: "They had to follow the money."

But it doesn't mean he is prepared to give up on his dream. "These investors and scientists are average age 45; they don't feel the urgency I do. I don't have 10 years; I went to West and asked what it would take to get the old-age cure back on track immediately. He told me $1bn would crack it in just one year."

Quarles is now knocking hard on the doors of private sources of wealth - Ross Perot, Bill Gates, the sheikhs of here and there - "everyone I know who has a billion to spare."

He lobbies furiously for his Curing Old Age Disease Society, writing regularly to world leaders, urging them to fulfil their responsibility to senior citizens. Ignore us at your peril, he warns: "Like an onlooker at a gang-rape, each Congressman will be guilty of the fatal neglect of millions of innocent citizens, and could be held responsible in a court of law!"

Is he senile? There is certainly a waver in the voice and a wateriness in the eyes, but overall Quarles comes across as a pretty sharp cookie. A geophysicist with an MSc from the California Institute of Technology, he still goes to work every day, managing to divine oil in between writing lucid begging letters.

Is he merely pathetic? No one can deny there is enormous pathos in the notion that eternal life lies only just beyond your reach: "I've got the cells left to put me back where I was at 45, if only they can be made to divide in time," he sighs, voice cracking with emotion.

Quarles desperately wants to be around to see the brave new world he foresees as a result of billions of people gearing up to live forever: "It could be our only authentic prospect for balancing budgets and retiring gigantic national debts. Education will be in huge demand; dreadful wars and other stupid activities that carry a high risk of death will become very unpopular and therefore avoided. Pollution might finally be eradicated, as we will have time to reinvent Planet Earth as a heavenly spot."

But without the billion, it could all happen after he's gone. So twice- divorced Quarles is seeking a new young bride as insurance against his failure to achieve immortality: "None of my three daughters is interested in having children, so I have an urgent need for descendants. I'm looking for a very pretty, sexy, smart 30-year-old willing to marry me and have kids - there's nothing wrong with my sexual capabilities."

He has encountered hostility to his efforts to speed the search for eternal life. "I can't get beyond the secretaries of most of the 50 billionaires I've written to," he says, "so I'm not even sure they've had my letters. Such feedback as I've had indicates - amazingly - that people don't want to live forever. They don't think I should, either - they think I'm just a selfish old man who should move over and make room for the young folks."

He is now targeting the Sultan of Brunei and has a convincing new argument for those who object to the idea of eternal life: "There is no danger of overpopulation because only 10 per cent will be alive to benefit from a cure for old age - the rest are ardent on killing themselves with over- indulgence. Of the rest a certain proportion is tired and just can't face the prospect of going back to work till they're, say, 200. They seem willing to tolerate the horror of a slow, painful and humiliating death from old age. They are wimps, more afraid of living than dying.

"My answer to them is simple - if you like things as they are and you just want to stay home, continue collecting your social security and die, why, then you don't have to take the cure! The rest of us are looking at the greatest achievement the world has ever known - and we should have the guts to overcome our fear and fight for it."

Miller Quarles will be the subject of 'QED' on BBC1 at 10pm tonight.

Could we really live forever? A scientist replies

There is such a thing as eternal life. We already have it and we know its name: it is called cancer.

The growth of cells in the human body is under delicate control. They grow by duplication - the cell splits into two "daughter' cells each identical to the other - a process which is confusingly labelled "cell division" by the biologists. The rate at which cells duplicate themselves (or divide) will vary from organ to organ and from time to time. Cells contain within their DNA both an accelerator and a brake pedal for reproduction, because their growth has to be regulated and balanced. If our liver cells suddenly started dividing faster than they should, the liver would grow and squeeze surrounding organs out of existence. This is precisely what happens when someone contracts cancer: tumour cells are those which have escaped the control mechanisms and are reproducing out of control.

Making human cells divide for ever has already been done. Researchers routinely culture "immortalised" cell lines in laboratory glassware, a technique which has been known for several decades.

The trick in making a living human being live for ever is not to show that his or her cells can be made to divide, but to get all the different tissues in all the different organs to grow at the optimum rate. It is the detailed control and balance which is important and with today's technology and scientific knowledge impossibly difficult. For if the control goes wrong, the outcome is cancer.