Never have so many spent so much trying to predict the thoughts of so few. And yet the Federal Reserve Open Market Comittee still managed to take almost everyone by surprise.

Not only did the Fed cut its core Fed Funds rate by 0.5 percentage points, down to 4.75 per cent, but it also cut the largely symbolic discount rate, at which it lends to banks, by the same amount. Not only that, but the accompanying statement said the Fed would “act as needed to foster price stability and sustainable economic growth” - a form of words that puts no limitations at all on its future actions. And the vote to take such extreme action was unanimous.