The SDLP has warned it might refuse to serve in a new power-sharing Executive at Stormont if London and Dublin concede changes in the rules for electing the First and Deputy First Ministers demanded by the DUP.
The Irish Times has learned that the warning was delivered by the SDLP leader, Mr Mark Durkan, to the Taoiseach, Mr Ahern, and the British Prime Minister, Mr Blair, during the Leeds Castle negotiations two weeks ago. Although the Ulster Unionist leader, Mr David Trimble, is believed to be considering the same option, it is understood the strength of Mr Durkan's opposition to the rule change sought by the DUP was a major factor in preventing further progress at Leeds Castle.
The co-equal First and Deputy First Ministers are required to be elected on a joint ticket with the support of a majority of those Assembly members designated "unionist" and "nationalist".
The Democratic Unionists have submitted a number of alternative proposals which would separate the two posts and avoid DUP members having to elect a Sinn Féin Deputy First Minister, and the two governments appear eager to facilitate a change in the rules.
Speculation that London is on the verge of doing so was fuelled by the release of a speech which was to have been made to the Labour conference in Brighton on Tuesday by Northern Ireland Secretary Mr Paul Murphy before he was taken ill.
Mr Murphy's text said the institutions of the Belfast Agreement need to develop and "must be vital and responsive to changing circumstances, not sculpted from stone, beyond amendment or improvement".
This prompted an angry response yesterday from Sinn Féin's Mr Martin McGuinness and from Mr Durkan, who insisted the current arrangement for jointly electing the First and Deputy First Ministers contained "a vital cross-community ethic".
Confirming his opposition to any change, Mr Durkan said the DUP was in fact proposing to "carve up" the power between the two sides, in effect "offering an accommodation of avoidance which isn't the way to change the politics of Northern society".