The prime minister has vowed to force banks to put their off-balance sheet liabilities into their books.

Speaking to Sky News yesterday, Gordon Brown signaled that it was 'not acceptable' that banks could fail to declare bad assets and that he wanted 'all companies to bring out their bad assets and put them back on their balance sheet so the financial system can move forward'.

Banks have faced widespread criticism for the huge special vehicles they helped set up and partly supported, but which did not need to be declared on balance sheet under the accounting rules at the time.

The precise extent of risk that fell on the banks has been unclear to investors, and the IASB is working on plans to develop parallel balance sheets to show the liabilities.

The interview is to be screened on Sky News tonight.

Shadow chancellor George Osborne said: 'Gordon Brown now says he wants to " clean up" the City. He seems to forget that he is the man who, in ten years as chancellor, created the current system of regulation. For ten years he boasted about his achievements. Today he is trying to disown them.'

Further Reading:

Read about the IASB's response to the credit crunch