LONDON - A defiant British Prime Minister Tony Blair has rejected calls by rebels within his party to name the day he will stand down, saying it would "paralyse" government.

After one of the most bruising weeks of his nine years in power, Blair vowed to forge ahead with market-inspired education and other reforms and to fight "all the way" traditional Labour Party leftists trying to block them.

Speaking at his monthly press conference in London, he also confirmed that he saw ambitious Chancellor of the Exchequer Gordon Brown, the finance minister who has been waiting impatiently in the wings, as his obvious successor.

"To state a timetable now would simply paralyse the proper working of government, put at risk the necessary changes we're making for Britain and therefore damage the country," said the 53-year-old leader.

Blair announced after Labour's third election victory in May last year that he would serve a full third term in office but not run for a fourth when the next general election takes place, before May 2010.

But poor local election results last week, after a series of politically damaging ministerial mishaps and failings, revived pressure within the party for a timetable for his departure and a transition of power to Brown.

The prime minister retorted that setting out an exit date now would be exploited by leftists seeking to turn the tide against reforms undertaken by a party he had steered toward the centre with massive electoral success.

"That way lies not a fourth-term victory but a defeat and a return to opposition, and I will fight that all the way," he said.

He confirmed Brown was his top choice to succeed him and said he would tell Labour parliamentary colleagues later Monday that he would honour pledges to ensure a "stable and orderly transition to a new leader".

He also said he would stay on to fulfill his election mandate for reform of healthcare, pensions, schools and justice.

Critics claim Labour is distracted by the looming change in leadership, with members either still supporting Blair or lining up behind Brown.

Labour members say Blair will face colleagues at Monday's meeting who are angry at his "ruthless" cabinet reshuffle in the wake of Thursday's municipal council results, Labour's worst since it took power in 1997.

The reshuffle saw the prime minister sack his home secretary, demote his foreign secretary, take powers off his deputy prime minister and juggle other key top posts.

Blair admitted the furore surrounding axed home secretary Charles Clarke -- whose department failed to deport hundreds of foreign prisoners once they were released -- had caused "significant damage" to the party in the polls.

Analysts say Blair swung the cabinet axe to demonstrate his authority, put the scandals of recent weeks behind him and give new purpose to his party, but the moves failed to quell calls for a clear handover of power.

Some 50 rebels have now signed up to a draft letter demanding a timetable for a "dignified, orderly and efficient" leadership transition to be set out by July.

A BBC radio survey of 104 Labour backbenchers found 52 who believed Blair should stand down within a year.

Calls on Blair to resign also came Monday from David Cameron, leader of the main opposition Conservatives who scored well ahead of Labour in Thursday's English council elections.

"I think the sooner he goes the better, because I don't see how his authority can recover," Cameron said.

As to his eventual successor, Blair said there was no doubt Brown as prime minister would continue the reform programme and Britain's close alliance with the United States.

"I believe that those people who maybe feel or hope that Gordon would take the Labour Party in a different direction from New Labour are -- on the basis of the discussions that I have had with Gordon -- completely mistaken," Blair said.