DUP leader Peter Robinson has raised the possibility of his party merging with the Ulster Unionists to prevent Sinn Féin being entitled to the First Minister role in a future Northern Ireland executive.

This development comes after negotiations between Sinn Féin and the DUP broke down. Sinn Féin has moved to review its participation in the current power-sharing administration at an Ard Comhairle meeting in Dublin tomorrow.

The controversy caused by a BBC spotlight programme about Iris Robinson, Mr Robinson's wife, has produced unexpected political consequences.

The DUP began face to face talks with Sinn Féin. It was trying to sort out contentious issues that had dogged its power-sharing administration, like a date for the devolution of justice and policing matters.

Sinn Féin seemed to have an advantage in those talks and the Robinson story had weakened the DUP and left it vulnerable to seat losses if Assembly elections were triggered.

When those negotiations broke down and Sinn Féin called an Ard Comhairle, the odds on an election increased.

Now the DUP has responded. Peter Robinson is talking up the idea of his party merging with the Ulster Unionists.

Such a merger would be difficult for the two organisations but it would allow unionists block the possibility of Sinn Féin being returned as the largest single party and in line for the post of First Minister.