Tony Blair is expected to leave No 10 about seven weeks after announcing his departure

He has already said he will leave No 10 by September, but there has been speculation about the precise timings.

He appeared to rule out suggestions he might announce his departure before, or straight after, this week's elections.

The PM, whose announcement would prompt a seven week leadership process, said: "I'll make my position clear next week, I'll say something definitive then."

Mr Blair's comments, in an interview with GMTV, come as he celebrates the 10th anniversary of the general election that saw him sweep to power.

Speculation he would use the occasion to announce his retirement was firmly denied last week by Downing Street.

Stormy relationship

Attention is now focused o­n Wednesday or Thursday next week, after the planned resumption of power sharing in Northern Ireland - seen as o­ne of the biggest achievements of Mr Blair's time in office.

We were perhaps too ready to place emphasis o­n our management of the media in those early years of government Peter Mandelson Send us your comments

Mr Blair's comments would appear to rule out an announcement in the immediate aftermath of Thursday's elections in Scotland, Wales and English local authorities, which are expected to be bad for Labour.

According to press reports, Mr Blair will use his retirement announcement to endorse Gordon Brown's leadership bid - in a final act of reconciliation with the chancellor, with whom he has enjoyed a stormy relationship.

Mr Brown has, meanwhile, heaped praise o­n Mr Blair in an article to mark his 10 years in power.

Writing in The Sun newspaper, Mr Brown said he was "honoured" to call Mr Blair his "oldest friend in politics", while admitting there had been "ups and downs" along the way.

Coronation

He praises Mr Blair for standing shoulder to shoulder with America after the September 11 attacks, for bringing the 2012 Olympics to London, his role in the Northern Ireland peace process and his handling of the death of Diana, Princess of Wales.

And - in a further sign of an impending Brown coronation - EU Trade Commissioner and key Blair ally Peter Mandelson predicted the chancellor would succeed Mr Blair in Number 10.

"In all probability, Gordon Brown will follow Tony Blair. He will now have been able to fulfil his ambition and his desire to lead the party and be prime minister," he said.

But Mr Mandelson said it was up to Labour Party members to decide the future direction of the party.

"It's up to the party to decide whether it wants to be New Labour and build o­n what we've done and to create a new New Labour."

Media management

Mr Mandelson, who was o­ne of the key architects of New Labour, also admitted the party focused too much o­n media management during its first years in office.

The former Northern Ireland secretary said it was not until late in the first term that Mr Blair concentrated more o­n policies.

"We were perhaps too ready to place emphasis o­n our management of the media in those early years of government, rather than concentrate o­n a more policy driven process," said Mr Mandelson.

He added: "I acknowledge it, but I think it was put right after the first few years. "

Mr Blair will continue to be prime minister until a new Labour leader is elected, which is expected to happen at the end of June.

The prospect of a Cabinet-level challenge to Mr Brown has all but disappeared but he could still face a contest with either John McDonnell or Michael Meacher from the left of the party.