Germany's top judge has issued a blunt warning that no further fiscal powers may be surrendered to Europe without a new constitution and a popular referendum, vastly complicating plans to boost the EU's rescue machinery to €2 trillion (£1.7 trillion).
Andreas Vosskuhle, head of the constitutional court, said politicians do not have the legal authority to sign away the birthright of the German people without their explicit consent.
"The sovereignty of the German state is inviolate and anchored in perpetuity by basic law. It may not be abandoned by the legislature (even with its powers to amend the constitution)," he said.
"There is little leeway left for giving up core powers to the EU. If one wants to go beyond this limit – which might be politically legitimate and desirable – then Germany must give itself a new constitution. A referendum would be necessary. This cannot be done without the people," he told newspaper Frankfurter Allgemeine.
The extraordinary interview comes just days before the Bundestag votes on a bill to revamp the EU's €440bn bail-out fund (EFSF), enabling it to purchase EMU bonds pre-emptively and recapitalise banks.
Tensions are running high after it emerged over the weekend that officials are working on plans sketched by the US Treasury and the European Commission to "leverage" the firepower of the EFSF to €2 trillion, in conjunction with lending from the European Central Bank.