Over 60 per cent of workers are worried about the prospect of a longer working life to support themselves through retirement as research showed the population of employees working beyond the age of 50 was growing.

Research from Aviva found the equivalent of 20m working people in the UK are concerned about having to work longer due to not having sufficient pension funds to be able to retire and a continuous rise in the state pension age.

The department for Work and Pensions yesterday reported a record number (10.6m) of workers over the age of 50, a rise of 32 per cent (2.6m) over the past decade.

The data showed in the age group 35-49 nearly nine in ten adults are currently working, but this drops to five in ten by the time people reach the 60-64 age group.

Some of this population may have chosen to retire early, but many will have not, according to Aviva.

The rise in the state pension age also plays a role in people having to work longer as it is the largest single source of income in retirement (43 per cent) for the average pensioner.

State pension age has been set at 65 for men since 1925, and was equalised for women last November. It is set to rise to 66 by 2020, 67 between 2026 and 2028, and 68 between 2044 and 2046.

Alistair McQueen, head of savings and retirement at Aviva, said although people had to continue working to support themselves, the data showed many were struggling to do this, meaning they may be worse off in retirement.

Mr McQueen said: “As the state pension age rises, millions of workers will seek to keep working through their fifties and beyond. But the continuing fall in employment participation as we age suggests many are struggling in this endeavour.”

The DWP’s data also showed a significant increase in the number of women working into their 60s, with a majority of women now in employment between ages 60 and 65.

Last month (August 19), a think tank suggested that the state pension age should increase to 75 by 2035.

The proposal – which also included raising the state pension age to 70 by 2028 – was made by the Centre for Social Justice, chaired by Iain Duncan Smith MP, former secretary of state for Work and Pensions, to tackle the challenges posed by an ageing society to the UK’s fiscal balance.