Britain is facing isolation in Europe after David Cameron vetoed a revision of the Lisbon treaty, prompting a majority of EU members to agree to draw up their own deal outside the architecture of the union.

In one of the most significant developments in Britain's 38-year membership of the EU, the British prime minister said early on Friday morning he could not allow a "treaty within a treaty" that would undermine the UK's position in the single market.

The move marked a victory for Nicolas Sarkozy, who had been pressing for an inter-governmental agreement among the 17 members of the eurozone to underpin tough new fiscal rules for the single currency. "We could not accept this," he said of Cameron's demands.