This will constitute a key moment in that both Sinn Fein and the Ulster Unionist parties must either accept or reject the joint paper on what is seen as the most contentious issue of all.
The two governments are believed to have developed a position based on last year's detailed report of the multi- party talks chairman, the former US Senator George Mitchell. He said flatly that neither republicans nor loyalists would decommission arms before talks, and that the best prospect lay in the possibility of decommissioning during the process of all-party talks.
The endorsement of this position means that a key moment is about to arrive both in the existing talks process and in Tony Blair's efforts to bring about a fresh IRA cessation. The British and Irish governments have been drawing closer since Mr Blair became Prime Minister, and this agreement underlines a new closeness between them. The key point will come, however, when republicans and Unionists give their reactions to the new joint stance.
Gerry Adams, the Sinn Fein president, last night promised his party would "study very carefully whatever proposals on decommissioning the two governments had agreed".
Final agreement between the British and Irish governments was achieved during private talks between Mr Blair and his outgoing Irish counterpart, John Bruton, on the fringes of the UN environment summit in New York. A Downing Street official confirmed the leaders had agreed in principle on the "basis of how we might move forward" towards a settlement on the issue.
While Mr Bruton told reporters the deal should permit "a rapid forward movement" in the talks, British officials were more circumspect. They insisted that any agreement would only be of value if it also proved acceptable to the other parties involved. Those would include Sinn Fein and the IRA itself, which have been seeking flexibility on decommissioning, as well as the Unionists who cling to a hardline approach.
A clear note of caution was also struck by the Prime Minister himself yesterday. "It isn't just the UK and Irish governments talking to each other; all sorts of things have to take place," Mr Blair insisted after the Bruton meeting. "This has to be done in conjunction with other parties."
The terms of the proposals should become clear tomorrow when the Prime Minister is due to make his first important Commons statement on Northern Ireland policy. His unwillingness to talk about the substance of his agreement yesterday was in part due to his concern not to pre-empt that appearance.
There was a long period of friction between Dublin and the Conservative government because of John Major's insistence that decommissioning of arms by the IRA would have to occur in parallel with them being allowed to join the talks.
During his visit to the US Mr Blair has been cajoled by both President Bill Clinton and the Vice-President, Al Gore, to find some way to move the peace process forward.
Mr Bruton told Irish radio: "Sinn Fein and the IRA are one and the same organisations. I believe that all of the issues that they have raised about the seriousness of the talks have been fully answered now."
Of the likely Unionist reaction, he said "their anxieties have been fully taken into account in the agreement we have reached".
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