"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.