Germany, UK urge global economic overseer

"We are prepared to consider radical options. The old ways have not worked. We've got to rebuild the financial system," he said.

The International Monetary Fund, set up by the Bretton Woods agreement in 1944, was outdated and focuses on cleaning up the mess when a country faces currency and debt crises. A different approach was needed, he said.

"What you've got to do is have a preventative facility which deals with crisis prevention rather than crisis resolution," said Brown, who will host a G20 leaders summit in April."