Dr John Hamill, a senior social sciences lecturer at Leeds Metropolitan University, said many would need to work longer because successive governments had devalued the state pension.

The state pension age will rise to 68 by 2046, when there are likely to be only two workers for every pensioner. The Government, which has no plans to raise the retirement age further unless there are "dramatic changes", says people must work longer to ensure future generations are not left footing a huge bill.

This stance has cross-party support, and the charity Age Concern believes many over-65s will relish the chance to work longer.

Dr Hamill said it was time for the Government to increase the value of the state pension to stave off a widening gap be-tween rich and poor in old age.

"Since 1979 the whole thrust of policy has been to decrease the role of the state in providing pensions and transferring that role to the market. Responsibility then gets transferred to the individual, and that's fine if you have a highly paid, professional occupation.

"But for the majority that is not the case; they are increasingly reliant on the state pension and one consequence is that people will be forced to work longer."

Last summer the Government announced an overhaul of the system. By around 2050 someone with a good working record can expect to receive a weekly state pension of about £145 in today's terms, Ministers claim.

Plans for Personal Accounts, a new low-cost range of pensions aimed at encouraging people on low and medium incomes to save for the future, are also being considered by Parliament.

State pensions will be linked to earnings by the end of the next Parliament at the latest.

Pensions Minister Mike O'Brien said: "In 1926 a man reaching 65 could expect to live for about an-other 10 years and a woman 13 years on average. Today a man reaching 65 can expect to live for about another 21 years and a women 24 years on average.

"So it's very important that we increase state pension age gradually so that future generations aren't left footing the bill for an ageing population."

Shadow Work and Pensions Sec-retary Chris Grayling said people should "have greater flexibility to work on beyond retirement age, with suitable safeguards for employers", adding: "We need better pension provision insofar as the nation can afford it."

James Player, of Age Concern York, said: "People are living longer and staying fitter longer, and it is nice for people to feel that, if they want to, they can carry on working... There is a huge amount to be gained by employing older people."

What the parties propose

Tories: Pensioners could be saved from having to sell their homes to pay for residential care. Considering American scheme whereby those who save enough to pay for one or two years' care could be freed from further costs. Want to see greater use of direct payments and individual budgets that give people control over their care.

Labour: Huge overhaul of state pension system planned.
Personal Accounts, a new low-cost range of pensions aimed at encouraging people on low and medium incomes to save for the future, being considered by Parliament.
State pensions linked to earnings by the end of next Parliament at latest.

Lib Dems: Immediate income guarantee of £124.05 per week for single pensioners. Hope this will end means testing and benefit women and groups outside the traditional nuclear family.