Tony Blair's efforts to talk up the underlying strength of the British economy were overshadowed yesterday by signs of a renewed rift with his finance minister over British entry into the euro.

Mr Blair had intended to use his speech yesterday at the Confederation of British Industry's annual conference in Birmingham, west Midlands, to deliver an upbeat assessment of the UK's ability to weather the looming global downturn.

However, his message was obscured by the appearance of a fresh division between himself and Mr Gordon Brown, Chancellor of the Exchequer - an impression that the Prime Minister's aides believe was intentionally fostered by the Chancellor.

Publicly, Mr Blair used his speech to deny any difference between himself and Mr Brown.

But privately, the Prime Minister's office was not hiding its anger that the Chancellor's own speech to a CBI dinner on Sunday night was spun as damping down the prospects for early entry to the single currency.

The Chancellor let it be known that he saw his speech as a corrective to the Prime Minister's euro-enthusiastic speech at last month's Labour party conference.

Mr Blair's allies feel they were tricked by Mr Brown's supporters, who depicted an approved and seemingly uncontentious speech as something that appeared hostile to the euro.

Mr Brown had stressed the five economic tests on whether to join the euro would be "comprehensive and rigorous", and he published a paper raising a number of potential obstacles to entry.

But yesterday, aware of the destabilising effect such rifts have on his government, Mr Blair tried to quell talk of a new division saying: "The policy on the euro has not altered an iota."

However, he did light upon the most positive phrase in Mr Brown's speech to the same gathering, stressing that the benefits of the single currency "in terms of stability, trade and investment are plain to see". Along with Mr Brown, he also raised the standard of EU economic reform, saying "a single currency makes a proper completion of the single market essential".

The Prime Minister also used his speech to press the economic importance of the conflict in Afghanistan, declaring that the war on terrorism was as much a fight for business as it was a battle for national security.