Gordon Brown ruled out further European integration for at least a decade yesterday as he sought to counter calls for a referendum on the latest transfer of power to Brussels.

Mr Brown left Lisbon insisting that the treaty agreed did not presage “fundamental change”. He was immediately contradicted by one of the architects of the original EU constitution, who said that the new treaty contained all of its essential measures.

Speaking at the end of the summit, Mr Brown said that he had won agreement for an EU declaration in December ruling out further institutional changes “for many years”. Asked how long the moratorium would last, the Prime Minister pointed out that some of the provisions in the existing treaty did not come into effect until 2017.

“I will not support further institutional change over the next period,” Mr Brown said, effectively threatening to veto any more treaties.

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But Jose Socrates, the Prime Minister of Portugal, said: “This treaty is not the end of the story because there is no end.”

Mr Brown’s task of selling the latest treaty to a domestic audience was made even more difficult as it was hailed as making the same fundamental changes as the defunct constitution. Valéry Giscard d’Estaing – the French President who oversaw the original EU constitution – said that the reform treaty “takes up the entirety of the institutional progress contained in the constitutional project . . . the proposed measures remain intact.”

As Mr Brown flew home to Britain, David Cameron repeated his demand for a referendum. He said that lengthy parliamentary scrutiny was no substitute for seeking the approval of the country. “I don’t think members of Parliament have the right to transfer that power away without asking the British people first,”he said. However, Mr Cameron and his Shadow Foreign Secretary, William Hague, are not without problems of their own. They face a backlash from Eurosceptics in their party after refusing to give a commitment to scrap the reform treaty.

They are under pressure to promise that they would hold a referendum if they were elected even if the treaty is ratified during the present Parliament.

Tory activists began protesting yesterday after Mr Hague again declined to spell out what the Conservatives would do if the treaty went through the Commons and was ratified across Europe. Several people writing on the Conservative website said that Mr Cameron was risking a repeat of the grammar schools row.

The official Conservative line is that this is something that will be discussed in the future and the priority now should be getting a referendum under this Government. They believe that would almost certainly mean the public rejecting the treaty. But there were signs yesterday that party leaders know they may have to move further. Asked by The Times for clarification of the position, a Conservative Party spokesman said: “If the EU treaty is ratified without a referendum it will clearly lack democratic legitimacy. We will make our decisions about the implications of that in due course.”

When he was asked on BBC Radio 4 whether he would repeal the treaty Mr Hague replied: “That is something we will have to look at. But we are looking to get people to realise now that we can get a referendum on this.”

But that is not enough for a large number of Conservative MPs. Led by William Cash and John Redwood, they have signed a Commons motion calling for a referendum on the reform treaty “before or after ratification”.

Tony Blair was proposed as the first “President of Europe”, a post created by the EU reform treaty, by President Sarkozy of France. Gordon Brown said: “Tony Blair would a great candidate for any significant international job.”

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