The Prime Minister angrily dismissed claims that Tony Blair had written off his chances of winning at the ballot box, vowing to "get on with the job".

But he was also forced to offer an explicit apology for the 10p tax rate debacle - which saw him stage an embarrassing climbdown in the face of a backbench rebellion last week.

Campaigning in the North West of England ahead of crucial local elections, Mr Brown was asked if he was "sorry" that the changes had been botched.

He replied: "Of course, because it's unfortunate when things go wrong for people and we've tried to sort that out immediately over the last few days.

"But I do stress, as a result of the Budget, far more people are better off, people who are on low incomes are better off, people who are in poverty as families or as pensioners, many have been taken out of tax altogether as a result of the decisions that we have made."

Senior Cabinet colleagues moved to shore up Mr Brown's position after Labour's former chief fundraiser Lord Levy launched a searing attack on Sunday.

The peer claimed Mr Blair was convinced his successor could not beat Tory leader David Cameron in a general election, and had been "disappointed" by the party's recent slide in the polls.

But Mr Brown hit back: "I think Mr Blair's office has made it clear that this is not an accurate reflection of what Mr Blair has said."

In an interview with the BBC, he added: "I'm going to concentrate on the job ahead, on the priorities that matter for the British people and not on gossip or rumour, or statements made by one or two people. I'm going to concentrate on getting on with the job."