Nearly a third of people in their 40s have no plans at all to fund their retirement and one in ten say they will 'work until they drop'.
That was the conclusion of a retirement planning study conducted by Aviva.
Researchers found worries about being able to afford their 'ideal retirement' means millions of over 40s are expecting to carry on working until they physically can't continue.
The study of 2,000 over 40s found that while the average adult would like to retire around the age of 60, one in five believe they will be working right until the bitter end.
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More than three quarters said they were worried about being able to afford all they have planned during their retirement. Another 64 per cent were concerned about simply paying for day-to-day living costs.
But despite these fears, around three in ten over 40s had no plans in place to fund their retirement.
Even of those that have a financial plan, 64 per cent admitted it's probably not going to be enough to do everything they want to do.
And almost two thirds of those surveyed wished they had started to plan for their retirement much earlier.
More than half did not have any idea what sort of sum they need to save in order to be able to achieve the kind of retirement income they are hoping for.
Clive Bolton, managing director of retirement solutions at Aviva, said: "Worryingly, it seems there are a large number of people who are so concerned about what their financial situation is going to be like, they are beginning to consider the possibility that they will always be working.
''I'm sure there are a small number of people who simply don't want to give up work, but most would rather spend their retirement doing what they want to do, rather than continue to work.
''And while some will be working to ensure they have enough money to have the kind of retirement they are hoping for, it seems there are some who will still be getting up every day to go to work simply to pay the bills.
''Your state pension is unlikely to cover everything you want to do during your retirement and cover unexpected expenditure, so it's important to have some kind of financial plan in place to provide additional funds to give you some breathing space."