The world's first anti-ageing drug will be tested on humans next year in trials which could result in people being able to live healthily well into their 120s.
Scientists now believe it is possible to stop people growing old and consign diseases such as Alzheimer's and Parkinson's to history.
Although it might seem like science fiction, researchers have already proven that the diabetes drug metformin extends the life of animals, and the Food and Drug Administration in the US has now given the go-ahead for a trial to see if the same effects can be replicated in humans.
If successful it will mean that a person in their 70s would be as biologically healthy as a 50-year-old.
Ageing expert Prof Gordon Lithgow, of the Buck Institute for Research on Ageing in California, is one of the study advisers. He said: "If you target an ageing process and you slow down ageing then you slow down all the diseases and pathology of ageing as well. That's revolutionary. That's never happened before.
"I have been doing research into ageing for 25 years and the idea that we would be talking about a clinical trial in humans for an anti-ageing drug would have been thought inconceivable.
"But there is every reason to believe it's possible. The future is taking the biology that we've now developed and applying it to humans."
Ageing is not an inevitable part of life because all cells contain a DNA blueprint which could keep a body functioning correctly for ever. Some marine creatures do not age - or grow weaker as time passes - at all.
However, over our lifetime billions of cell divisions must occur to keep our bodies functioning correctly and the more times cells divide the more problems grow, and cells can no longer repair damage.
Scientists think the best candidate for an anti-ageing drug is metformin, the world's most widely used diabetes drug which costs just 10 cents a day.
Metformin increases the number of oxygen molecules released into a cell, which appears to boost robustness and longevity.
When Belgian researchers tested metformin on the tiny roundworm C. elegans the worms not only aged slower, but they also stayed healthier longer. Last year Cardiff University found anecdotal evidence that when patients with diabetes were given the drug metformin they lived longer than others without the condition, even though they should have died eight years earlier on average.
The new clinical trial called Targeting Aging with Metformin, or TAME, is scheduled to begin in the US next winter. Scientists from a range of institutions are currently raising funds and recruiting 3,000 70 to 80-year-olds who have, or are at risk of, cancer, heart disease and dementia.
A baby girl born today is now expected to live to an average age of 82.8 years and a boy to 78.8 years, according to the Office for National Statistics. But if the results seen in animals are reproduced in humans, lifespan could increase by nearly 50 per cent.