Mr Tony Blair appealed to Northern Ireland politicians not to "throw away the best chance for peace we will have this generation" in an address to the House of Commons yesterday.
The British Prime Minister told Ulster Unionists the plan presented at Stormont last week contained a "failsafe" guarantee on decommissioning. The plan was a challenge to all parties but if it went through, people would know within days if the paramilitaries were serious about decommissioning their weapons, he said.
"After 30 years of bloodshed, grief-stricken families, terror-torn communities, is it not worth waiting 30 days to see if these undertakings are fulfilled?" Mr Blair asked to Labour cheers.
Under the plan, within days of the executive being formed the IRA must make a statement that it is prepared to decommission and then within weeks of that begin actual decommissioning.
After the statement the North's First Minister, Mr David Trimble, said that by calling on the UUP to join an executive before the IRA had handed over any of its guns and bombs, Mr Blair was leaving the political initiative with the IRA. "You are asking us to sacrifice the democratic principle to expediency and you are asking us to take a gamble on an ineffective and unfair safety net." Flanked by Northern Secretary Dr Mo Mowlam, Mr Blair told a crowded House the Good Friday agreement offered all the people of Northern Ireland the prospect of permanent peace.
"I believe it is still the only true way forward for Northern Ireland," he insisted.
"Of course, difficulties remain. There is still violence, though much of it by loyalists opposed to the Good Friday agreement.
"There is still conflict and bitterness, as we can see at Portadown, where I will continue to work for a settlement of the Drumcree issue.
"But life in Northern Ireland has been improved immeasurably since the Good Friday agreement. Normality has returned to most parts of the province.
"Whatever their disagreements, the two sides now talk to one another regularly."
Mr Blair stressed that both sides of the community needed certainty for the peace process to work.
"Unionists want certainty that decommissioning will happen and a guarantee that, if it does not, they will not be left in an executive with those who refuse to do so.
"Republicans want the certainty that unionists are serious about participating in a genuinely inclusive government.
"Our agreement last Friday provides both."
Outlining the terms of the plan, Mr Blair said there would have to be a "definitive statement of intent" by paramilitaries to decommission within days of the executive body being launched in Northern Ireland.
If it did not happen - to the satisfaction of the International Commission on Decommissioning under Gen John de Chastelain - the executive would be "unwound", he told MPs. "So we will know within days whether the decommissioning is to happen or not."
A further time limit was set for actual decommissioning. Should that not happen, then again "the failsafe kicks in".
Mr Blair stressed: "Should default occur, the institutions are suspended automatically, whilst we find a way forward.
"We are all then, in effect, back to where we are now but with two vital differences.
"The blame for default is clear and the parties are then free to move on in an executive without the defaulting party."
He said: "I cannot make the other parties agree to a new executive. I cannot force anyone to sit in a government with anyone else.
"But I can make sure that Sinn Fein do not continue in an executive with the Ulster Unionists should there be a default of the de Chastelain process."
Mr Blair told unionists they now had a much better deal than was on offer at Hillsborough.
"This provides a guarantee of a complete process of decommissioning plus a failsafe that protects fully the interests of the unionists."
"If last Friday's agreement is put through, we will know within days whether the paramilitaries are serious about decommissioning their weapons."
If the undertakings were fulfilled, real peace would come.
"If they are not, then we will know that the challenge of true democracy was too much for those linked to paramilitary groups.
"Either way, we will know. Discuss the detail, debate it, engage. But don't throw away the best chance for peace we will have this generation."
Tory leader Mr William Hague said: "The obstacle to progress is not Ulster Unionist leader David Trimble and his party, who have done all that is required in the agreement, but the terrorists, republican and loyalist, and their political representatives who have failed to get rid of their arms.
"Against this background the anxieties of the unionists are wholly understandable."
Mr Hague added: : "It is clear there is no cast-iron guarantee that the IRA will commence decommissioning their weapons."