Imagine that. A nation state (member state) ought to have a say in how its money is spent. What a radical new concept.

Germany’s top court has ruled that the European Central Bank’s mass bond-buying to stabilise the eurozone partly violates the German constitution.

The ruling relates to government debt worth €2.1 trillion (£2tn; $2.3tn) bought by the ECB since 2015, but not purchases in the coronavirus crisis.

The Constitutional Court in Karlsruhe says there is not enough German political oversight in the purchases…

The plaintiffs are a group of German academics, including a former leader of the far-right Alternative for Germany (AfD), Bernd Lucke. They argue that the purchases violate the EU ban on one eurozone member subsidising the debts of another.

It is now up to the ECB to explain how its mass bond-buying programme is “proportionate”. The Bundesbank could pull out if it is not satisfied, in three months’ time – which would be a big blow to the eurozone.