Numbers 10 and 11 Downing Street have moved to rebut allegations that relations between the prime minister and the chancellor have gone from bad to worse.

According the press reports, Gordon Brown has recently asked Tony Blair "several times" when he is going to step down.

Speculation over a rift between Brown and Blair has resurfaced after unnamed "allies" of the prime minister briefed the press on the subject.

Following the reports, spokesmen for both the chancellor and his boss denied that tensions had reached breaking point.

"Ever since this government was formed, people have wanted to say that the Blair-Brown relationship is doomed to fail, partly, they argue, because of historical precedent. The press haven't had that and it's obviously become very frustrating," said a spokesman for the prime minister.

"It is a vital and strong relationship and it remains so. The idea that the chancellor has been demanding that the prime minister move over is simply untrue.''

Number 11 had earlier taken the rare step of issuing a public denial that Blair and Brown had entered into the famous "Granita" pact.

The comments came after Wednesday's Telegraph newspaper that there had been "a sharp deterioration in relations" between the Downing Street neighbours.

"Things are pretty bad," a source claimed. "Gordon keeps asking Tony when he is going to go."

It has been suggested that the pair agreed to a "secret pact" after John Smith's death in 1994.

The deal is said to have resulted in Tony Blair being given a free run for the leadership in exchange for the prime minister stepping down midway through a second term.

This is said to be the price Brown extracted from Blair when he made clear he would not stand in the leadership election.

Both men denied that such a pact existed when pressed on the matter during the 2001 general election campaign.

But with Blair approaching the halfway point of his second premiership this summer, Brown is reported to be increasingly agitated that the deal will not be honoured.

Sources close to the prime minister have hinted that he is "determined" to continue into a third term.

Blair is said to be keen to achieve his twin aims of modernising Britain's public services and winning a euro referendum.

The relationship between the two men, who have been long-standing political and personal friends, is said to have hit rock bottom since entering government.

Policy rifts have recently broken out over university fees and foundation hospitals.

Brown's chief adviser, Ed Balls, outlined the differences when he said there were "limits" to what the private sector could achieve in public services.

The chancellor's critics say privately that he has exacerbated these differences in order to boost his popularity within the Labour Party.

But his political standing has been hit by recent downturns in the economy and a raft of tax increases.