The proportion of Britain's population aged over 65 is set to increase over the coming decades, according to the latest research.

The data is set to add to concerns that Britons are failing to save for their retirement and will add to the pressure on ministers to deal with fears of a mounting pensions crisis.

Data from the Office for National Statistics revealed that between 1961 and 2001 the number of people aged 65 and over rose by 51 per cent to 9.4 million.

And the number of those aged over 65 will overtake the number of under-16s in just 11 years. By 2025 there will be at least 1.6 million more people over the age of 65 than people under 16.

While the state pension age is already being raised to 65 for women over between 2010 and 2020, the ONS also noted that there would be other policy implications for politicians to consider.

"The increase in the number of pensioners has policy implications, placing greater demands on health, social services and social security arrangements," it said.

Other data released as part of the Social Trends survey also indicated that Britain remains a profoundly unequal country, with the distribution of wealth massively favouring those at the top.

The richest one per cent of Britons owned 22 per cent of the total wealth of the household sector in 2000. In contrast, half of the population shared just six per cent of total wealth.

Among the health indicators cited in the survey, figures for tuberculosis showed a rise of nearly a fifth over the past decade to 7200 cases in 2001.

But life expectancy at birth has increased for all social classes, said the ONS.