Asset values slump by £65bn in 2008

The accountancy firm said the falls were equivalent to five years' worth of current pension contributions from these companies - or a return of -17pc over the year.

It noted FTSE100 schemes would now have an aggregate deficit of £130bn using typical assumptions for cash funding.

Deloitte pensions partner David Robbins said a significant recession in the UK had serious implications for pension scheme funding - with the prospect of low (or negative) economic growth depressing asset prices and interest rate cuts pushing up the prices of government bonds and the value of scheme liabilities.

He said trustees were also likely to ask companies for more cash to plug the ballooning deficit.

Robbins added: "Management should engage with trustees to reach an acceptable agreement on cash contributions which takes into account the level of contributions the company can reasonably afford.

"The solution will usually involve non-cash options such as charges over assets or escrow arrangements."

He added: "The events of the last year show that companies need to be comfortable with the amount of investment risk they are taking relative to their financial resources."