Eurosceptics' worst fears appeared to be realised today, when the president of the EU Commission admitted his mission was to create a federation of member states.
Jose Manuel Barroso's use of the phrase will be a form of vindication for prominent eurosceptics like Ukip's Nigel Farage or the Tories' Daniel Hannan, who he branded "eurosceptic-populist-extreme-nationalists".
The EU commission president urged supporters of the European project not to hesitate at the idea of a federation.
"Let's not be afraid of the word: we will need to move towards a federation of nation states," he said.
"Europe has a soul. This soul can give us the strength and the determination to do what we must do.
"No one will be forced to come along. And no one will be forced to stay out."
The president admitted any federation would require "a new treaty" because it involved "the sharing of sovereignty".
The idea of a federation has often been raised by eurosceptics as the logical end result of the European project, but it is usually denied by continental leaders because it suggests a far greater loss of national sovereignty than the public are prepared to accept.
Many officials in Strasbourg and Brussels readily describe themselves as federalists, however.