Only around a third of pensioners were able to give up work when they reached state retirement age last year as millions struggled to fund later life, a new study has shown.

Research firm Mintel found that just three in ten pensioners retired when they reached state pension age in the year to February 2012, compared to 48 per cent of people in the previous year.

The firm's Lifestyles of the Over-55s report, which was obtained by the Telegraph, shows that just one in eight people had retired last year because they could afford to do so.

Joanne Segars, the chief executive of the National Association of Pension Funds, claimed that the research underlines the fact that many people can not afford to stop working once they reach state pension age as they have failed to plan properly.

"Sadly many people are finding their retirement plans turn out to be a mirage. They get near, realise they can't afford it, and see the day when they'll stop working slip further into the distance," she told the news provider.

It is estimated that around 650,000 people retire each year but this figure is likely to fall over the coming years.