In mid-December, Paul Volcker told a crowd of some of the world's best-known financiers that commercial banks should not be engaging in proprietary trading. He said: "I am not alone in this, and in fact I think that I am probably going to win in the end." A little over a month later, he has backed up these words.

Volcker, the former US Federal Reserve chairman known as "Tall Paul" for his imposing six-foot seven-inch frame, was speaking at the Future of Finance Initiative at the end of last year. Earlier at the event, executives including Michael Spencer of Icap and Richard Gnodde of Goldman Sachs had presented their view of the future of finance.