The civil servants, politicians, diplomats and assorted hangers-on collectively known as “Brussels” have every reason to be cheerful as they return from their long summer break. For the first time in seven years, the economy of the euro area is growing faster than that of the US. Unemployment is falling in France and Germany and public finances are looking healthier.

But a mood of gloom still hovers over Brussels. The European Union has not recovered from referendums in France and the Netherlands last year, which saw the defeat of a proposed constitution for the EU.