A deepening rift is developing between Britain's Foreign Office and the Treasury, the country's finance ministry, with the Foreign Office increasingly convinced that the Chancellor, Mr Gordon Brown, has become hostile to British membership of the euro.

Foreign Office ministers and officials are furious that Mr Brown has become the darling of Britain's Eurosceptic tabloid press because of his reported cooling towards the euro.

They believe the media coverage is allowing Mr Brown to restate his claim to succeed Mr Tony Blair as prime minister.

The Foreign Secretary, Mr Robin Cook, and Mr Brown have been rivals in the Labour Party for years, but Treasury control of the government's euro policy is causing deep frustration in the Foreign Office.

"We will need to have a new chancellor after the next election to say yes to the Treasury's five tests on euro membership," said a senior Foreign Office figure.

Mr Cook wants to promote the potential benefits of euro membership now, in the belief that the referendum planned for the next parliament can be won only after a protracted campaign.

Yesterday, Mr Keith Vaz, Minister for Europe, said the euro zone had enjoyed "low interest rates, low inflation rates and stability" over the past year, "and the prospect is for this to continue".

But Mr Brown appears reluctant to extol the possible advantages of euro membership, other than to say the Treasury will judge participation on its five economic tests. He is concerned about deepening public scepticism towards the EU, and determined the next election should not be dominated by the euro.

Mr Brown wants an election fought on his stewardship of the economy, and prefers the Foreign Office to focus on persuading people of the benefits of EU membership.

Another senior Foreign Office figure criticised Mr Brown's cautious approach to the euro.

"The flaw in Gordon's position is if nobody makes the case for the euro now, why the hell will anyone want to vote for it in a referendum?" said the Foreign Office figure.