Researchers claim to have developed a new controversial 'lifespan' test that can tell how long a person will live by determining the rate of ageing.

The blood test estimates how fast someone is ageing by measuring the length of microscopic structures at the ends of each chromosome called telomeres, which keep each chromosome from falling apart when cells divide, they said.

Telomeres shorten after each cell division and animal studies have shown that a high percentage of short telomeres in blood cells is associated with a shorter-than-normal life expectancy, which is why blood tests could provide a guide to ageing and life expectancy.

More than 100 Britons have already taken the test to see how fast they are ageing, and which might be used in the future to indicate statistically how long they have got left to live.

The company behind the test expects it to be used as part of the standard medical check-up.