Tony Blair may announce a firm departure date next April in an attempt to limit Labour's losses in mid-term elections next May.
But the Prime Minister is under mounting pressure to make his intentions clear this month and some close allies are worried that he could be forced out by his own MPs.
Prominent supporters of Gordon Brown, his most likely successor, led a backlash against Mr Blair's refusal to disclose his departure plans in a newspaper interview yesterday. They said his uncompromising approach, in which he told his critics to stop "obsessing" about the leadership, had backfired.
Mr Brown is said to be worried that Mr Blair gave no sign of moving towards the "stable and orderly transition" he has promised. He hopes the Prime Minister will think again.
As normally loyal MPs joined the clamour for Mr Blair to reveal his plans, allies said Mr Blair would be more specific about his departure date before elections to the Scottish Parliament, Welsh Assembly and English local authorities next May.
"He will have more to say about timing - but not in the next few weeks," one close ally said. "He is conscious of the significance of the elections."
An announcement when the election campaigns start in April is believed to be a leading option among Mr Blair's inner circle. That could see him leave Downing Street in the summer or early autumn after a three-month Labour leadership contest.
As Mr Blair visited Edinburgh yesterday, Scottish and Welsh MPs and assembly members were among those who spoke out most strongly against him. They fear Labour will lose power in Edinburgh and Cardiff if he has not announced his departure or stood down before the elections.
Wayne David, a parliamentary private secretary and MP for Caerphilly, said: "There's a need now for the agenda to be carried forward and, to be meaningful, there's a need for a change of leader." Labour MPs are now discussing signing an open letter pleading with Mr Blair to say when he will quit, or to ask a delegation of senior party figures to deliver such a demand to him face-to-face.
His critics will not decide their next moves until Labour conference in Manchester in three weeks. But one said: "The mood has changed as a result of the interview. The question now is not whether we do something but when. The interview was counterproductive. The conflicting signals have made people even keener to get a public declaration about a date."
Brown allies said they were furious that Mr Blair did not slap down Blairite "outriders" who have criticised the Chancellor but appeared to brand all MPs demanding clarity and certainty about his plans as Old Labour.
Some backbenchers are frustrated at Mr Brown's refusal to "go for the jugular." But he is unlikely to move against Mr Blair. "He wants a stable and orderly transition. The moment we give up on that, we might as well hand the next election to the Tories," said one Brown supporter.
Blair allies denied his interview had backfired. They said criticism had come mainly from "usual suspects" and that middle-of-the-road MPs were satisfied with Mr Blair's approach.
Tony Woodley, leader of the transport workers' union, told GMTV's Sunday programme Labour was being hit by "confusion, disillusionment and dissatisfaction" and change was needed "now".
He said: "This is a major problem now as we drift further and further down in the polls, so far down now that if an election was run tomorrow Labour would be most likely to lose.
'Tony has got to hand over'
* George Mudie, Labour MP for Leeds East and former deputy chief whip: " Tony has got to show some leadership, recognise he has got his place in history and take the orderly steps to hand over...
"He said he is going and the party needs firm leadership, the country needs leadership, so we have got to move on - otherwise it is going to be a very messy conference."
* Andrew Smith, Labour MP for Oxford East and former Work and Pensions Secretary: "I would have thought it's clear to everyone that the debilitating uncertainty over the leadership can't go on - it's bad for the country, bad for the Government, bad for the Labour Party, and ultimately bad for Tony Blair himself ...
"It's very clear that the leadership issue has to be sorted out sooner rather than later."
* Sarah McCarthy-Fry, Labour MP for Portsmouth North: "We are stuck in this quagmire and we cannot get out of it because everything swings back to the leadership ... I am so disappointed at him coming out now and just shutting the door. The speculation is damaging the partyand could damage the country and I don't think him refusing to say anything is going to solve it."
* Julie Morgan, Labour MP for Cardiff North: "It would be better if we knew that timetable before facing the electorate next May ... I would prefer that we had changed leader by next May because I don't think it would be advantageous to Labour to go into major elections without knowing what was happening."
* Wayne David, Labour MP for Caerphilly: "There is a need for renewal of the party and the Government now and for that to happen the speculation about the Prime Minister's future must be brought to an end. That is why we need clarityabout the Prime Minister's position."
* Clive Betts, Labour MP for Sheffield Attercliffe: "His refusal to discuss the issue is going to dominate the conference.I think at some point the PM has to talk about it. The idea that somehow anyone who wants to raise this issue wants to turn the clock back to the 1980s and is really Old Labour in disguise is a nonsense."Reuse content