It became clear yesterday in a brief, ten-minute telephone call from Mr Blair to David Trimble, the Ulster Unionist leader, in Belfast that the Ulster Unionists would vote down the plans but they would not walk away from the peace process.
Mr Trimble said: "The fact that we had a difficulty and not met the target date is no excuse for people to walk away from the process."
That was in marked contrast to Ian Paisley, leader of the hard-line Democratic Unionist Party, who emerged from a meeting with Mr Blair at Downing Street declaring the peace document "dead" and accusing the Government of an "Iscariot act of betrayal" over its plans for disarming the IRA.
Although the result will be seen as a setback for the peace process, the Government yesterday made clear its determination that negotiations on Northern Ireland's future should nonetheless open as scheduled on 15 September.
The exact format of those talks is not however clear. Rejection of the two governments' joint position on de-commissioning will pose important technical and philosophical questions in that the multi-party talks, as presently structured, are supposed to rely on "sufficient consensus" within both communities to proceed. Since the three rejectionist parties led by Mr Trimble, Mr Paisley and Robert McCartney together won 89 per cent of the Unionist vote in last year's pre-talks elections, there will clearly be no basis for arguing that there is Unionist agreement for anything the present talks come up with.
This means that the Government will have to come up with a new formula for talks in readiness for the 15 September starting date. In doing so it will be mindful of indications that the state of Protestant opinion may not be accurately reflected in the electoral arithmetic.
Mr Paisley's withdrawal was attacked by David Ervine, of the Progressive Unionist party, which has paramilitary associations. He exclaimed: "These people are running away when they're most needed."