Employees potentially have unrealistic beliefs about how much they will have to live on as well, according to new research by Prudential.

This expectation gap was found to be at its widest among younger workers.

The results showed that workers of all age groups were confident that they would be able to afford to retire significantly earlier than their respective State Pension ages.

Anyone born after 5 April 1978 will have to wait until their 68th birthday before they can start to claim the State Pension.

However, the under-35s interviewed expected, on average, to retire before they get to 64. The trend of estimating retirement dates at least four years short of the State Pension age was also evident among both the 35 to 54 and 55 and over age groups.

For people currently aged 35 to 54, their State Pension age will be between 66 and 68 depending on when they were born. However they estimate they will, on average, retire before their 63rd birthday.

For those aged 55 and over, the State Pension age will be up to 66 years and seven months, but on average they expect to have retired before they reach 62 years of age.

Many younger people felt they would be able to retire before the State Pension age, which researchers said could perhaps be explained by the fact that they estimated retirement income significantly higher than that expected by 2015 retirees.

Prudential’s data released earlier this year highlighted that the average person planning to retire in 2015 expects to have an annual retirement income of £17,000 – 45 per cent of whom will receive their income from a defined benefit (or ‘final salary’) pension scheme, down from 52 per cent in 2008.

Stan Russell, a retirement income expert at Prudential, said: “Although people of all ages are expecting to be able to retire well before State Pension age, life expectancy continues to increase, with the average retirement now lasting nearly 20 years.

“It is important not to underestimate quite how long retirement savings will need to last. Our previous research has shown that the average retiree in 2015 is 60 years old, but I often encourage people born in the 1970s and 80s to be prepared for the fact that they are likely to be working in some form or other until they are much older.”