Gordon Brown, the British prime minister, is privately ready to sacrifice the Lisbon treaty rather than allow Ireland’s No vote create a two-tier Europe.

Despite the outcome of the Irish referendum, France, Germany and senior Brussels officials have insisted there should be no delay in implementing the European Union blueprint.

Sources close to Downing Street, however, say that Brown would rather the treaty collapse than see individual member states left trailing in a two-speed Europe.

The demise of the treaty would take the heat off Brown as he faces down renewed calls for Britain to hold its own referendum. If Europe presses ahead without Ireland, it would set a precedent for a two-speed club, with Britain also likely to be stuck in the second tier.

A Downing Street source said: “The legal position on this is very clear: the treaty cannot come into force until all 27 countries have ratified it.”

One senior British government official said anyone who thought the Irish vote could be ignored was “living in cloud-cuckoo-land”.

The leaders of the EU’s 27 members states will meet this week in Brussels, but Nicolas Sarkozy, the French president who takes over the EU presidency next month, is dismissing the Irish vote as a hiccup.

“The Irish people have spoken. We must accept it,” Sarkozy told a joint news conference alongside President George Bush, who was visiting France. “Today, 18 European states have ratified. The others must continue to ratify — that is also the intention of Gordon Brown, who told me so on the telephone yesterday — so that this Irish incident does not become a crisis.”

Frank-Walter Steinmeier, Germany’s foreign minister, went further, stating the Lisbon treaty provisions, which include the creation of a permanent EU president and the widespread abolition of national vetoes, could be implemented without Ireland. “Ireland, for a period of time, could leave the way free for the integration of the other 26 member states,” he said.

Jim Murphy, Britain’s Europe minister, yesterday told BBC Radio 4’s Today programme: “Only those who previously wished to dance on the grave of this treaty, even before the Irish referendum, are declaring it dead.”

Murphy also said that it was up to the Irish government to find a solution to the impasse. “The Irish government need to come to the European council meeting next week to tell us how they think we should be taking this forward, based on the sovereign decision of the Irish people,” he said.

In private, the mood among senior Whitehall officials is more pessimistic. “No one wants to come out publicly now and say ‘the treaty is dead’,” said one. “But by the end of the week, after the Brussels summit, that could well be the case.”

In Brussels, meanwhile, after the initial shock of the Irish result, senior officials have already begun considering the complex legal mechanisms that might still allow the stricken treaty to be implemented.

The details of any “two speed” plan have yet to be worked out, but it is likely to involve common treaty devices such as “opt-outs” and “protocols”. One exotic idea being actively considered is a “legal bridge” linking Ireland with the rest of the EU. Another scheme is to link aspects of the Lisbon treaty to the “accession treaty” of Croatia when it joins the EU in late 2009 or early 2010.

In Britain, leading Labour figures pronounced the Lisbon treaty dead and urged Brown to halt the slide towards European integration. Jon Cruddas, the Labour MP for Dagenham in east London, said: “Stock clearly needs to be taken of the Irish vote. We can’t just press on relentlessly with the treaty and disrespect what the people have said.”

Vaclav Klaus, president of the Czech Republic, stated that the Irish vote effectively spelt the end for the treaty reforms.

“The Lisbon treaty project ended today with the decision of the Irish voters and its ratification cannot be continued,” Klaus said.

“The result is hopefully a clear message to everybody. It is a victory of freedom and reason over artificial elitist projects and European bureaucracy.”

Klaus was the only EU leader to break ranks, as everyone else called for member states to carry on with ratification. The Czech presidency is a largely ceremonial post and it is highly unlikely that the Czech government — whose country is one of eight states still to ratify the Lisbon treaty — will in fact abandon the process, according to Brussels insiders.

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