Brown claims red lines 'victory' for EU treaty

The Prime Minister virtually claimed victory over France and Germany who had attempted to water down a series of opt-outs and vetoes demanded by Britain in return for agreeing the "son of constitution" blueprint.

But Mr Brown's apparent success opened up an even more fraught argument over whether he should call a referendum before signing the new treaty.

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Speaking at No 10 after talks with European Commission President José Manuel Barroso, he confirmed that Britain is largely happy with a draft text due to be agreed in Lisbon next Thursday.

"I have got to be absolutely sure that the British national interest has been safeguarded in every one of the issues that we have raised," he said.

"When we look at the detail of it, I believe that we have succeeded in our negotiating objectives."

The Prime Minister warned French President Nicolas Sarkozy and German Chancellor Angela Merkel that he would scupper next week's talks if they tried to ambush him.

"If we were to go beyond our red lines [areas of national interest] we could not accept the amending treaty," he said.

Mr Barroso praised Mr Brown's "hard fought" stance during intense negotiations and said he believed the final text fully respected Britain's bottom lines.

But Mr Brown's claim will not satisfy Tories who argue that a referendum should be held because the draft treaty hands powers to the EU.

Downing Street continued to hold out the theoretical prospect of Mr Brown calling a referendum if the treaty breached his red lines - effectively a threat to veto it by other means, since a Yes vote would be unlikely in such circumstances.

His official spokesman said: "We would either veto the treaty or there would be a referendum."

Tories say the idea of a referendum on a treaty that the Government did not support is ludicrous.