Having been an early supporter of the euro, I now consider my engagement to be the biggest professional mistake I ever made. But I do have a solution to the escalating crisis.

I have three reasons for my change of heart. First, politicians broke all promises of the Maastricht treaty. Not only was Greece let into the eurozone for political reasons, also the fundamental rule, “no member to exceed its yearly budget deficit by the equivalent of 3 per cent of gross domestic product”, was broken more than a hundred times. Mandatory punitive charges were never applied. To top it all: the “no bail-out” clause was wiped out in the wake of the first Greek rescue package.

Second, the “one-size-fits-all” euro has turned out to be a “one-size-fits-none” currency. With access to interest rates at much lower German levels, Greek politicians were able to pile up huge debts. The Bank of Spain watched the build-up of a real-estate bubble without being able to raise interest rates. Deprived of the ability to devalue, countries in the “south” lost their competitiveness.