Northern Ireland faced an uncertain political future tonight after the British government resisted republican and nationalist opposition and postponed new elections to the Stormont Assembly.
Even though the Taoiseach Mr Ahern urged Mr Blair to press ahead with the May 29th poll, the British prime minister decided to delay the vote until at least the autumn because of what he said was the IRA's failure to declare an end to its campaign.
The Downing Street decision was being seen as the biggest setback to the peace process since the signing of the Belfast Agreement five years ago, and outraged the Sinn Féin leadership of Mr Gerry Adams and Mr Martin McGuinness.
Just over four and a half days into the campaign for 108 seats at the Stormont Assembly, Secretary of State Mr Paul Murphy confirmed the postponement - leaving all sides in Belfast to consider an unprecedented political farce, and a £1 million-plus bill for an election that never was.
Direct rule from Westminster, re-introduced last October after the Assembly was suspended amid claims of an IRA spying operation inside Stormont, will continue for the foreseeable future.
Both governments felt the IRA's insistence that there would be no activities to undermine the Agreement fell well short of what was needed.
An election now without agreement would simply make an eventual agreement less likely, Mr Blair said.
It is the second time the election has been put on hold. It was first planned for today, May 1st, but then delayed to give the governments more time to come up with a blueprint on the way forward, including proposals for the IRA to effectively wind up.
The British and Irish declaration, which was prepared last month and released today, also confirmed year-by-year plans to scale down security, transfer policing and justice powers to Stormont, as well as offering an amnesty to fugitive republicans wanted for questioning for terrorist crimes, some going back more than 25 years.
Agreement had been more or less reached on how those key issues were to be implemented, but even though IRA signalled there would be no more violence and eventual total disarmament, it was their failure to be more specific about plans to end arms procurement, targeting, training and punishment beatings which scuppered a deal.
The confidential IRA statement sent to the British and Irish governments three weeks ago was expected to be released later.
Mr Ahern disagreed with the postponement. He said in Dublin: "It will cause more problems than it solves."
But even though he revealed his opposition, the postponement is unlikely to create any new Anglo-Irish rift.
Mr Blair is to meet with the Taoiseach in Dublin on Tuesday when he is expected to renew his demands on the IRA.
Mr Blair insisted his decision was not at the behest of the Ulster Unionist leader Mr Trimble who did not want an election without an IRA declaration.
He said Mr Adams and Mr McGuinness had achieved an extraordinary feat and brought republicanism and the peace process a very long way.
But "creative ambiguity", which helped in the past, helped no more. Five years on from the signing of the Agreement, it was a different world inside and outside Northern Ireland.
There could be as much bitter and acrimonious political argument and debate as they liked, but from now on all problems had to be resolved politically.
Mr Adams later welcomed the decision by the governments to pushlish their joint declaration but criticised Mr Blair for putting off the elections.
Mr Adams said he had given Mr Blair "precisely the answer he asked for at the time" when he issued his statement yesterday.
"Now he's looking for a different answer", he added.
The Sinn Fein leader went on to say it was absurd for Mr Blair to suggest problems in the North be solved politically and then proceed with deferring the May 29th elections. He called on people to demonstrate for their right to vote.
Throughout the morning Northern parties became increasingly concerned the British government would pull plans for the vote on May 29th after Mr Adams's latest attempt to explain the IRA's position failed to lead to progress yesterday.
Ulster Unionist leader Mr David Trimble rejected the statement from Mr Adams yesterday, and Downing Street insisted it needed more clarity on the IRA's attitude to paramilitary activity.
But republicans insisted they were not prepared to engage in further "word games" with the government. Sinn Féin chairman Mr Mitchel McLaughlin said a postponement of the elections would be called just to suit Mr Trimble's party.
SDLP leader Mr Mark Durkan argued last night Mr Adams's statement reflecting the IRA position was "clearly within the hinterland of what was so clearly asked of them". He had called for the release of the British and Irish governments blueprint and all other statements.