One in every 15 Britons now in their mid-eighties will live to be more than 100 as a result of improved nutrition and medical treatment, official figures show.

There were 9,300 people aged 100 or more in Britain last year - an increase of almost 1,000 on 2005, according to the Office for National Statistics (ONS).

The findings come just a month after ONS data showed that for the first time there were more pensioners than children under 16.

There are at present seven women over 100 for every man, but this ratio is declining as male life expectancy is improving at a faster rate than that for women. The number of centenarians is increasing at about 5.4 per cent a year.

ONS said that the main contributor to the growth was increased survival between the ages of 80 and 100 as a result of improved medical treatment, sanitation, housing, living standards and nutrition. Mortality rates are expected to continue to improve throughout the 21st century.

The number of centenarians has risen ninetyfold over the past century as life expectancy has increased. There were about 100 centenarians in 1911, the ONS said.

Pamela Holmes, head of healthy ageing at Help the Aged, said: “The improvements in standards of living and medical care over the last 100 years have been staggering. This is reflected in the 9,300 people now living into their second century.”

She added, however, that the country had to take note not just of how much longer people were living, but also of their quality of life. “The evidence shows that we are now seeing quality of life in our later years falling behind life expectancy, but this need not be the case.

“By making healthy choices in mid-life, we can greatly improve our chance of living longer and better. Educating people in the importance of eating well, exercising and stopping smoking can make real improvements years down the line.

“The Government must also start thinking how society is going to adapt to an older population. How we design our housing stock, streets and transport will have a huge impact on how well we live in our older age, both now and in years to come.” Of those who were aged 85 in 2001, 6 per cent of men and 7 per cent of women are expected to celebrate their 100th birthday.

Until 1940s the average annual increase in centenarians was 1.9 per cent, but over the next 40 years - coinciding with the development of the welfare state - it rose by an annual average of 6.4 per cent.

Annual growth rates slowed between 1981 and 2001, reflecting the number of deaths in the First World War and the subsequent flu pandemic.

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