"I do think we need to get it in perspective, but without doubt, some of these big banks will see a reduction in profits as you have seen today."

Asked about the impact of the credit crisis on the UK economy, he said: "Despite this international uncertainty, which started from the problems in the US housing market, there are grounds for believing that we will get through this.

"We have a strong economy, its momentum will carry us through."

Mr Darling also defended the billions of pounds lent to Northern Rock, saying the bank still had assets of ?100bn.

Chairman and chief executive of Citigroup, Charles Prince, said his resignation "was the only honourable course" after the world's biggest bank built up billions in losses and write-downs from exposure to high-risk mortgage debts.

After Mr Prince stepped down, Citigroup revealed that it was facing losses of between $8bn and $11bn in previously undisclosed losses due to a decrease in the value of its $55bn portfolio of sub-prime loans.