Prime Minister Tony Blair reluctantly promised Thursday to resign within a year, hoping that revealing a general timeframe for his departure will appease critics who are calling for him to step down.

"I would have preferred to do this in my own way," Blair said. He refused to set a specific departure date, but said the annual Labour Party conference this month would be his last. The next conference is scheduled for September 2007.

"The precise timetable has to be left to me and has to be done in the proper way," he said.

Blair, who took office in 1997 and once commanded Labour with an unassailable authority, now appears to be at the mercy of demands from its restive lawmakers. It was not immediately clear whether his new exit strategy will be detailed and speedy enough to satisfy them.

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Labour loyalists urging Blair to leave office soon — or at least announce a departure date — have grown more vocal in recent weeks. Their protests have been fueled by widespread anger at his handling of the recent fighting in the Middle East and anxiety over Labour's slide in the polls.

Eight junior officials quit Wednesday to insist on Blair's resignation, and news reports said Blair and Treasury chief Gordon Brown, who is considered likely to be the next prime minister, had a shouting argument in Blair's office about a handover date. The two may have ultimately reached an understanding.

Brown, opening a children's sports tournament in Glasgow, Scotland, said shortly before the prime minister's announcement that while he like others had had questions about Blair's plans, he would support his decisions.

"When I met the prime minister yesterday I said to him ... it is for him to make the decision," said Brown, looking relaxed and cheerful. "I will support him in the decisions he makes."

"This cannot and should not be about private arrangements but of what is in the best interests of our party ... and the best interests of our country," Brown said.

Many within Labour were furious at Blair's refusal to break ranks with President Bush and call for an early cease-fire in Lebanon last month. It revived bitter memories of Blair's decision to join the Iraq war despite intense opposition in Britain.

White House spokesman Tony Snow said Blair and Bush still had a lot of work to do together.

"He's a valued ally," Snow said. "He is somebody whose counsel the president much values and cooperation the president depends upon. And at this point, we're not sitting around writing encomia for Tony Blair. We're instead busy working with him."

The prime minister led Labour to its third straight election win last year and has long said he would not seek a fourth term. Before Thursday, his most specific comment about quitting was a promise to give his successor time to settle into office before the next elections, expected in 2009.

His close Cabinet allies tried to quiet the clamor in the party with increasingly explicit suggestions this week that next year would be Blair's last in office.

But eight junior officials quit Wednesday rather than remove their names from a letter demanding that Blair step aside. A total of 15 Labour lawmakers wrote in that while they supported the centrist direction in which Blair had taken the party, he was no longer the right man to lead it.