According to the Maradona theory of monetary policy, as outlined by Sir Mervyn King, governor of the Bank of England, a central bank can let expectations that it will act – rather than actual action – do the work for it.

The theory is being tested right now by Mario Draghi, president of the European Central Bank, as his controversial “outright monetary transactions” bond-buying programme is forced to sit on the benches until the prime candidate for help, Spain, applies to the EU’s bailout fund.

As a quick reminder, the Maradona theory refers to the 1986 World Cup quarter final between England and Argentina. Diego Maradona scored a celebrated goal with a run from near the halfway line in which he beat five England players by, er, running in a straight line. Read more