Tony Blair's commitment to go within a year was not enough to silence some of his opponents in the party.
MP Doug Henderson, a close ally of Mr Brown, said it was not clear that the electorate now knew any more about the Prime Minister's intentions than they did before his statement.
Mr Henderson said: "It does not seem to me that the public know any more about the Prime Minister's retirement plans. People keep saying to me that the Labour Party must have a clear direction forward with clear priorities and a new leader before the elections in 2007."
And Graham Stringer, Labour MP for Manchester Blackley, protested that the Prime Minister's statement "doesn't take us any further".
"I don't believe by leaving the date up in the air it is going to stop the kind of debate and discussion that's been going on," he said.
But Blair loyalists sought to use the premier's comments to draw a line under the affair.
Sir Stuart Bell (Middlesbrough) told Sky News: "There is a sense of relief in the Parliamentary Labour Party. The Prime Minister has said very clearly he will not be here next September. Gordon Brown has accepted that situation.
"We have the Queen's Speech on November 15. We are going to settle down, get on with policy and have a policy debate as to where we should be going when the Prime Minister does step down. I think the Labour Party had a nervous breakdown in public this week."
Northern Ireland Secretary Peter Hain backed Mr Brown to succeed Mr Blair, but added: "After a difficult week, it is now time for us to get back to work and to focus not just on the task of securing an unprecedented fourth term, but also on delivering the third-term policy agenda on which we were elected only last year. Implementing those policies means an orderly handover, not a chaotic putsch."
Liberal Democrat leader Sir Menzies Campbell said: "The Prime Minister has only partially resolved the ambiguity. He has set a time limit, but not named a date. Speculation will continue, while the authority of Government drains away."
