Commenting on Bank of England Governor Mervyn King's call for a fundamental rethink of how the banking sector is structured, Brown said: "The difference between having a retail and investment bank is not the cause of the problem."

"The cause of the problem is that banks have been insufficiently regulated at a global level and we have got to set the standards for that for the future and we will be doing that at the G20 finance ministers' (meeting) in a few weeks' time," he told parliament.

(Reporting by Adrian Croft; Editing by Tim Castle)