European ministers have explicitly laid out their intentions to create a federal Unites States of Europe, directly contradicting the British Prime Minister, David Cameron’s claims that Britain will not be sucked into a European superstate should the people of Britain vote to remain within the European Union (EU).

Presenting his renegotiated deal on EU membership in February, Mr Cameron insisted: “Britain will be permanently out of ever closer union, never part of a European super-state.”

But the emergence of a declaration signed in Rome by European ministers five months previously to Mr Cameron’s announcement reveals that the intention on the continent is to press ahead with the creation of a federal Europe.

Not content with merely monetary union and free movement, the declaration, signed by the speakers of the national parliaments in Germany, France, Italy and Luxembourg states that they want to integrate a broad spectrum of policies. “It should include all matters pertaining to the European ideal — social and cultural affairs as well as foreign, security and defence policy,” the declaration states.

It adds: “We are convinced that new impetus must be given to European integration. We believe that more, not less, Europe is needed to respond to the challenges we face.

“The current moment offers an opportunity to move forward with European political integration, which could lead to a federal union of States.”

The Commission has denied all knowledge of the declaration. A spokeswoman told the Sunday Times: “I am not aware of any such initiative. This is not something related to the commission.”

But leader of the Commons, Chris Grayling, who has been sent the document, said: “This shows there are now serious plans for a political union, where those countries in the Eurozone move towards having a single government.”

He accepted Mr Cameron’s statement that Britain and Denmark would be exempt, but argues that in practice the arrangement would make very little difference.

“This new entity will still make our laws for us,” he said. “We will have very little say in what happens. We have to decide whether we want to be an independent country or whether we want to be caught up in what is heading fast towards being a United States of Europe.”

The emergence of the document comes mere days after it was revealed that Germany and the Netherlands are already pressing ahead with plans to federalise the European armed forces by merging their own national forces.

In doing so, they hope to create the nucleus of an EU Army which can be expanded. The Czech Republic has already entered talks on bringing her armed forces under German control.

Germany has so far taken over at least two Dutch army units, and a Danish warship is now under joint control by the German and Dutch navies.

The pro-Brexit former Minister Iain Duncan-Smith, who last month resigned as Work and Pensions secretary in protest at the government’s plans to cut benefits, has accused Mr Cameron and his Chancellor George Osborne of lying to the British people over the EU Referendum.

“What is being sold to the British people by the government at the moment is nothing short of a sham,” he said, adding: “I don’t think anybody arguing for ‘in’ now believes a word of what they’re saying, I just think that they have got themselves into a position where they have to now win this regardless, at all costs.”