At last, some good news...Britain's pensions are back in the black

They managed to wipe out the deficits that have dogged them since the dotcom crash seven years ago.

Final salary pension schemes run by Footsie 100 firms are now in surplus to the tune of £15billion after surging in value by £55billion this year, according to the accountancy firm Deloitte.

That erased a "black hole" of more than £40billion at the start of the year, and a £75billion shortfall in January 2006.

News that pension funds have returned to their healthiest state since the early days of the Labour government will go some way towards dispelling the depression that has seen consumers tighten their belts this Christmas.

The threatened global credit crunch and spiralling mortgage bills have led experts to predict that the economy will slide into recession next year.

Falling house prices and rising interest rates have helped to make it one of the most uncertain holiday periods in years.

The dramatic turnaround in Britain's pension industry is down to surprising resilience on London's stock market.

Despite the turmoil gripping the financial system, Britain's index of leading shares is due to finish the year with a modest gain.

That is good news for pension funds, which invest a large bulk of their members' cash in shares.

Big companies have also been pumping more cash into their pension schemes to erase potentially damaging deficits, according to Deloitte.

Aerospace giant Rolls-Royce recently injected £500million into its retirement fund, with newspaper group Trinity Mirror topping up its pension scheme by £100million. Final salary pension schemes, which guarantee members a retirement income linked to their salaries, have been a major headache for big companies over recent years.

Dramatic rises in life expectancy mean funds have had to bankroll their members for longer.

The crash on global stock markets after the 2001 dotcom

collapse also took its toll on pension funds. But share prices have staged a spectacular recovery since 2002.

And though the stock market could take a hit next year, the health of Britain's pension funds is likely to continue improving, according to Deloitte.

Number- crunchers at the auditing firm reckon the collective surplus could double to £30billion next year.

That is likely to persuade more big firms to farm out their pension schemes to specialist financial firms.

"Over 2008, companies will be looking to solve their pension problems for good," said David Robbins, a pensions expert at Deloitte.

"Transferring pension schemes to new specialist buyout companies is beginning to look viable," he added.

Heat magazine and Kiss FM owner Emap and wine retailer Threshers recently " outsourced" their pension schemes to third-party providers.

However, getting rid of a pension scheme can be fraught with difficulties, experts warned.

A £10billion deal to take Sainsbury's private collapsed earlier this year after its Middle Eastern buyers failed to reach agreement with the trustees of the supermarket chain's pension scheme.