There is one big disadvantage to a negative rate: it would amount to a tax on banks, since the overall level of central bank deposits must remain about the same 〓 like the game of Old Maid, each bank would be trying to pass on the money. Charles Goodhart, an ex-member of the Bank of England’s monetary policy committee, points out that if banks were lending, negative rates would not be needed; they only have themselves to blame.

At the very least, this would hand Mr Bernanke a new weapon. Only by experimenting will we find out if it has the firepower to break deflation.