Pension experts are expressing growing concern that the scheme to protect final salary pensions could be in trouble.

With pension shortfalls at a record high, the Pension Protection Fund (PPF), which acts as a safety net for workplace pensions, is in danger of being submerged by claims from bankrupt companies.

Some 91 per cent of final salary schemes do not have enough money to pay out benefits. The under-funded schemes have deficits of more than £228bn.

The PPF itself is also short of funds. Although it collects £700m each year from companies, this does not cover all its liabilities and the fund has a deficit of £550m.

The fund is already shouldering the weight of 62 failed schemes, including Lehman Brothers and Woolworths.

There are now fears that the collapse of just one more large company could cause the PPF to fail, leaving those in underfunded final salary schemes at risk of losing their entire pensions.

The National Association of Pension Funds, along with Vincent Cable, Liberal Democrat shadow chancellor, is calling on the government to take on responsibility for the scheme and act as guarantor, but the government has yet to comment.

Companies have asked the PPF not to increase levies and the government not to demand more contributions to pensions until the recession lifts.

The concerns emerge as a new survey from Punter Southall revealed that 60 per cent of pension schemes do not know how the recession is impacting their funding position.