It will lead to not only an economic but a political crisis. In 2012, when concern about sovereign debt in several periphery countries was at its height, it would have been possible to divide the euro area into two divisions, some members being temporarily relegated to a second division with the clear expectation that after a period – perhaps 10 or 15 years – of real convergence, those members would be promoted back to the first division.

It may be too late for that now. The underlying differences among countries and the political costs of accepting defeat have become too great.

That is unfortunate both for the countries concerned – because sometimes premature promotion can be a misfortune and relegation the opportunity for a new start – and for the world as a whole because the euro area today is a drag on world growth.

Germany faces a terrible choice. Should it support the weaker brethren in the euro area at great and unending cost to its taxpayers, or should it call a halt to the project of monetary union across the whole of Europe? The attempt to find a middle course is not working. One day, German voters may rebel against the losses imposed on them by the need to support their weaker brethren, and undoubtedly the easiest way to divide the euro area would be for Germany itself to exit.