The term “helicopter money” is derived from a vivid image created by the US economist Milton Friedman in which a central banker showers notes on a grateful populace. More recently, the notion has been promoted by Adair Turner, the former chairman of the UK financial regulator, in his book, Between Debt and the Devil. It has also won some favour from bond king Bill Gross and even real central bankers such as Ben Bernanke, formerly chairman of the US Federal Reserve, and Mario Draghi, president of the European Central Bank.

No one really envisages that money would be dropped from a helicopter. What they have in mind is that in a recession government would increase expenditure in a manner that would directly stimulate private sector spending. The ideal format in which to undertake the borrowing required is bank notes, which pay no interest and need never be repaid. That is why the idea of dropping currency from a helicopter has appeal.

But, of course, even if the lucky recipients of the helicopter drop went straight down to the pub to celebrate their good fortune, the publican would return the cash to the banking system by the end of the day, and the notes would end up back in the vaults of the central bank. The helicopter drop does not give households reason to hold additional notes in their wallets, shops to keep more cash in their tills, or banks to hold more currency in their branches.