There was a healthy air of competitive debate at last week’s Future of Finance Initiative, a conference run by the Wall Street Journal in the English countryside.

Paul Volcker, the former US Federal Reserve chairman known affectionately as "Tall Paul" for his imposing six-foot seven-inch frame, set the conference alight when he questioned what benefit, if any, financial innovation might have brought to the world economy. Lord Turner might have asked earlier this year whether some of what banks did was socially useful, but here was America's former top banker questioning whether they had done much that was financially useful either.