The study by British insurer Norwich Union suggests 22% of retired people over the age of 50 return to some kind of employment, be it full, part-time or voluntary.

It also says this figure rises as Britons get older, with as many as 34% of people aged between 65 and 74 coming out of retirement to find work.

It will be interesting to see whether people retiring 30 years from now will find themselves in the same position Ian Beggs, Norwich Union

But it is not money that is tempting most pensioners back to the workforce, so much as social interaction and the desire to keep active.

Ian Beggs, research director of Norwich Union, said that while some people find retirement a positive experience, "for others, the impact of giving up work for good is a real blow".

Keeping in touch

According to the survey, only 4% of people return to work because they need the money.

A large proportion of the so-called "un-retireds" choose part-time or voluntary work as a means of keeping occupied and giving something back to the community.

Reasons to 'un-retire'

Keeping active - 12% Helping the community -11% Social interaction -11%

More than 27% of those returning to work choose voluntary occupations.

"Of those people who have chosen to go back to some form or work, most have done so out of choice rather than necessity," said Mr Beggs.

"The feelings generated from retirement range from freedom, release and 'the great escape', to a sense of loss, no longer feeling like a contributor, and in some cases loss of self-esteem," he added.

People find their ideal post-retirement jobs most frequently through word of mouth - the survey suggests 34% of retired people find a work through friends or relatives.

Nearly two thirds of those questioned in the survey, carried out by Taylor Nelson Sofres, said they were against a compulsory retirement age; just 30% were in favour of it.

"It will be interesting to see whether people retiring 30 years from now will find themselves in the same position," said Mr Beggs.