Blair, who has long refused to publicly endorse his ally-turned-foe Brown to take over from him in 10 Downing Street, said the finance minister would make a "great prime minister".

"Within the next few weeks, I won't be prime minister of this country," Blair said in Edinburgh, 10 years to the day since the 1997 general election that saw his Labour Party swept to power.

But in his strongest hint yet that Brown will take over, he added: "In all probability, a Scot will become prime minister of the United Kingdom.

And in a clear reference to Brown he said: "That's someone who has built one of the strongest economies in the world and who I've always said will make a great prime minister."

As to his departure Blair told Britain's GMTV breakfast programme: "I will make my position clear next week. I will say something definitive then."

For his part, Brown was also in conciliatory mood, using a newspaper column to heap praise on his "oldest friend in politics".

But he brushed aside talk of his imminent promotion as he opened a new school in northern England. Instead, he said he was concentrating on campaigning for Thursday's municipal council elections.

Blair and Brown shared an office when they first became lawmakers in 1983 and were behind key reforms to the faction-riven Labour party that made it an electable proposition.

But their relationship has soured since, particularly over Brown's perception that Blair reneged on a deal to hand over power to him after a second term of office.

Supporters of Brown, allegedly with his blessing, mounted a "mini-coup" last September amid heightened tensions within Labour over Blair's foreign policy, forcing the 53-year-old premier to say he would be gone within a year.

Blair has so far refused to name the exact date but political observers have said they see May 9 or 10 as the day he will bow out.

Power-sharing government between Catholics and Protestants in Northern Ireland resumes the day before. Brokering the peace between the two sides has been seen as one of Blair's greatest achievements.

Blair's official spokesman dropped a clear hint Tuesday that an announcement would come immediately afterwards.

"Northern Ireland will be a big day and I think everyone recognises that," he said.

"And certainly in terms of our approach it has always been that we want to mark the occasion and mark the occasion properly but also let people focus on the achievement of the politicians there and not distract from that in anyway."

Blair and Brown's comments appeared to give the impression of party unity within Labour, which has been split along Blair-Brown lines since the former became party leader in 1994.

Brown's article in The Sun tabloid appeared under the headline "10/10 Blair's decade of achievement" and reflected on the prime minister's decade in power at home and abroad.

"I am honoured to call Tony my oldest friend in politics, of course with the inevitable ups and downs along the way, but still the longest partnership between prime minister and chancellor for 200 years," he said.

Returning the compliment, Blair hailed Brown's prudent stewardship of the British economy in the last decade.

"I have always said about him that he would make a great prime minister and I believe that," he told GMTV.

In Britain, the prime minister is the leader of the largest party in the lower House of Commons and a fresh general election does not have to be called if he or she resigns.

His announcement would trigger an internal election lasting seven weeks, meaning a decision on a new leader could be known on June 30 or July 1.

Nearly three quarters -- 73 percent -- of voters want a general election, however, should the successor to Blair simply take over as prime minister, according to a poll released on Tuesday.

The Communicate Research poll of 1,001 adults also found that a majority of Labour voters, 52 percent, wanted a general election to be called in a scenario where a new prime minister took over.