On the eve of the 2012 Olympic Games, Mario Draghi found himself in the august setting of Lancaster House in London’s royal district. He was a panellist at an official event intended to drum up foreign investment to the UK, but the president of the European Central Bank had weightier matters on his mind.

Europe’s single currency was disintegrating amid soaring borrowing costs in Greece, Spain and Mr Draghi’s native Italy. Speculation that the eurozone was heading for a break-up, with incalculable financial and political consequences, was rampant. It was time to draw a line in the crisis.

“Within our mandate, the ECB is ready to do whatever it takes to preserve the euro,” Mr Draghi said, pausing for effect. “And believe me, it will be enough.”