By Nick Assinder
Political correspondent, BBC News website
If Tony Blair made a mistake in believing the pre-announcement of his retirement would stop speculation over his future, then it follows it may have been a mistake to make the announcement.
That original statement in October 2004 came as the prime minister was about to be admitted to hospital for treatment of a heart problem and speculation about his future was at near fever pitch.
Stopping that chatter, which had already been gripping Westminster for months, was undoubtedly one of the prime objectives of the prime minister's shock announcement - although he said at the time his aim was also to be honest with the British people.
So a number of key questions remain in the wake of his new "admission" in an interview in Australia.
What were the effects of his unprecedented statement, would it have been better if he had said nothing, and what are his current intentions?
The last question is of particular interest to his would-be successors, notably Gordon Brown, who may not have been overly delighted by the signals coming from the prime minister's camp following his interview.
What is certainly true is that, just like Margaret Thatcher before him, Tony Blair had reached a point where questions over his future leadership intentions were being routinely asked, irrespective of his health problems.
They were not going to stop and the prime minister calculated his announcement was far better than suggesting, as Mrs Thatcher did, that he would go "on and on".
But it did not work. If anything, the statement may have made matters worse because it gave the prime minister's critics, and even some of his friends, another question to obsess over - exactly when would he go.
It ensured that, whenever the prime minister suffered any setback, his critics would claim it was now the time for him to stand down.
Brown is seen as successor
It also had what is dubbed the "second term president effect", that is
the consequences of not having to face the electorate again.
That can turn a US president into a lame duck, with the power of patronage, and consequential authority, fading, just as it can remove the caution he may otherwise exercise over policies or behaviour the electorate might reject.
It can also see the incumbent scrambling to secure a lasting, positive legacy.
Tony Blair's critics claim to have perceived all these effects at work in Downing Street since the last general election.
For example, some of those Labour MPs who rebelled over the prime minister's controversial education reforms were emboldened by what they saw as the prime minister's waning authority.
Others believed they were opposing a policy that was unpopular with their electors.
And virtually all believe the policy is seen by the prime minister as a key part of what he hopes will be his legacy.
Now, in the wake of his Australia interview, the prime minister appears to have signalled that he has a retirement date in mind, which he is keeping to himself, and that he has other key reforms to complete first.
Those reforms include the NHS and the House of Lords - major and highly-controversial issues unlikely to be solved overnight.
Thatcher wanted to go on and on
The Lords reform is seen by some as an attempt to move on from the "cash-for-peerages" row and the health reforms as a response to recent stories about serious problems in some hospitals.
And, while many Labour MPs will undoubtedly be happy for the prime minister to stay as long as he likes - with some even claiming his "mistake" was to have ruled out standing for a fourth time - others are champing at the bit.
The second group claim the prime minister is rapidly running out of time and should go before things turn really ugly - with more backbench revolts and resignation speculation escalating.
And Mr Blair himself will certainly want to avoid falling to the same fate as Margaret Thatcher, whose cabinet finally told her the game was up. So when will he go?
There is now increasing speculation that this year's party conference in September will be his last and that Mr Blair will leave Downing Street somewhere around his 10th anniversary as prime minister in May next year.
There are those, however, who even believe it could come sooner than that.
Either way, unless the prime minister reveals a date, this speculation will run right up until the day he goes.