British companies could be hobbled by £45 billion-a-year demands from their pension trustees just as the country slides into a recession.

Aon, the pension consultancy, gave warning yesterday that companies with final-salary pension schemes face a £225 billion bill from trustees because plummeting asset prices are exacerbating existing pension deficits. Trustees are likely to demand £45 billion a year for the next five years, research by Aon suggests.

The consultancy firm is forecasting that 2009 will be the bleakest year yet for companies with shortfalls in their defined-benefit schemes. Until the economic storm has passed, it wants the Pensions Regulator to relax the rules that allow trustees to force companies to raise their contributions to make good the deficits.

“The last thing companies need at the moment is another cash call,” Marcus Hurd, the head of corporate solutions at Aon, said. “Cash is the very thing everybody is in short supply of. Just as employers thought the economic news couldn't get any worse, they are likely to be hit by big bills to pay for their pension schemes.”

David Norgrove, the chairman of the Pensions Regulator, recently said that he believed the regime was already sufficiently flexible to allow for contributions to be reduced.

Aon's risk index, which tracks the top 200 companies that still run their own final-salary schemes, shows that 64 per cent of the schemes are now in deficit because assets held by them have lost £226 billion of their value in the past year.

The BBC is one of the biggest casualties of sliding share markets. The corporation's pension fund has had £1 billion wiped off the value of its equities over the past four months. Just under a quarter of the BBC's £8 billion fund was invested in UK equities, which are down by more than 45 per cent on this time last year.

Mr Hurd said that while he did not expect companies to go bankrupt because of cash demands from pension trustees, current regulations created a dangerous game of brinkmanship where trustees' duties required them to push for contributions when a firm was most vulnerable.

“Rather than an increase in pension scheme contributions, companies really need support from their pension schemes,” he said. “Sensible financial plans which ease pressures in the short term are required to ensure companies can meet their pension obligations in the long term.”

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