Financial regulators, central bankers and politicians around the world have become pretty good at issuing mutually contradictory instructions. They are more than happy to tell banks to bolster their balance sheets at the same time as ordering them to lend more to businesses and help kick-start the economy.

But deep down they must know banks can't save more money at the same time as they lend more money - there's just not enough money. It's got to be one or the other.