But the two leaders have yet to secure the support of key Northern Ireland politicians, with the largest unionist party still voicing significant doubts.

The deal was put forward amid fears of an outbreak of violence surrounding Sunday's controversial march at Drumcree by Protestant Orangemen, which has been banned from passing a nationalist housing estate.

David Eades in Stormont: A virtual deal

Under the plan announced after week-long marathon negotiations, Tony Blair and Bertie Ahern said they were hoping to see Northern Ireland's new cabinet or executive take up office on 15 July. Full power would then be devolved to the locally elected assembly on 18 July.

Within days the handover of weapons would begin, a process due to be completed by May 2000.

The conditional nature of their proposals was underlined by Mr Ahern, who called it "an agreement for consideration."

Tony Blair: We've got everything ready to go

Both the Ulster Unionists and the IRA's political wing, Sinn Fein, have yet to confirm they had accepted the plan.

The lengthy negotiations between the two sides have been stuck on one crucial problem - the handover of paramilitary weapons.

Bill Clinton: A chance to put an end to guns and violence

Speaking after the talks, Ulster Unionist leader David Trimble said his party had still not received any commitment on the issue of disposing of paramilitary weapons that his community could recognise.

For his part, Sinn Fein President Gerry Adams was more upbeat.

He said: "There will be an enormous sigh of relief across this island tonight and indeed around the world.

"I think everyone would warmly welcome the conclusion of our efforts."

Executive proposals

Speaking at the end of the talks, Mr Blair said: "It is the most historic opportunity for peace this land has known for years and years and years."

He said the government would trigger mechanisms to set up the power-sharing executive in the new Northern Ireland assembly on 15 July.

A Devolution Order is to be laid before parliament on 16 July, to take effect on 18 July, effectively giving power to locally elected politicians for the first time in a generation.

He also said that within the period specified by General John de Chastelain, the international commission on disarmament would confirm a start to the process of decommissioning.

Weapons report

The general's report on the decommissioning of paramilitary groups' weapons was published earlier in the day.

In the document, the commission said there were grounds for believing that republican and loyalist terrorists would disarm fully by next May, in line with last year's Good Friday peace accords.

The assessment was given by General de Chastelain, who said the process should start as soon as possible.

In particular, he said that Sinn Fein had given him the basis for believing that the IRA's arsenal could be fully decommissioned by May 2000.

Mr Blair said that decommissioning would begin within days of the devolution of power, and this would mean the actual handover of arms within weeks.

The process of handing over guns would have to be completed by May 2000, and failure to complete this would lead to the suspension of all institutions set up under the Good Friday Agreement.

All the parties now have a period of two weeks to consult their rank and file membership.

Mr Blair accepted that the talks process had now entered the "end game" in the runup to 15 July.

The groundbreaking deal from the two governments was welcomed by President Clinton, who has followed every stage of the negotiations.