Democratic Unionists, already furious at British army demilitarisation, will threaten to disrupt the work of the policing board when they meet Northern Secretary Peter Hain in London this morning following his latest announcement.
Mr Hain said yesterday he would extend the board's life by up to 12 months to provide "stability and continuity to continue its important work".
The DUP wants a new membership when the remit of the current 19-member body ends on October 16th. The party believes a new policing board line-up should reflect its strong electoral showing in the three most recent elections.
Unionists accused Mr Hain of a political ploy in holding open the door to membership of the board to enable Sinn Féin to take its seats should it alter its position on policing within the next year.
Mr Hain said: "I have given the current position of the Northern Ireland Policing Board careful consideration and I am well aware of the different positions from the parties on this issue.
"However, my overriding concern during these deliberations has been that the board, which successfully fulfils a vital role in policing accountability arrangements, is provided with stability and continuity to continue its important work. I hope that circumstances permit the board to be reconstituted before October 2006.
"I acknowledge that there are issues around the membership's numbers from a party political perspective but at a time of big change, we need some stability and continuity."
However, DUP board member Sammy Wilson said the decision was "a slap in the face for unionists by a secretary of state who will bend over backwards to satisfy a bunch of terrorists".
Speaking to The Irish Times he warned: "The secretary of state is looking for stability. Well he won't get it. We will not be acting predictably. The board will not run as smoothly as it has."
Asked if he expected to see Sinn Féin figures across the table when the board is finally reconstituted Mr Wilson said: "No I don't. If there are Sinn Féin people then there'll be even more frustration of the government plan than now." The decision was welcomed by board chairman Prof Sir Desmond Rea and vice-chairman Denis Bradley.
Mr Bradley said: "I'm very pleased with this decision, it's a very courageous decision given the backlash it has endured over the last couple of days. I of course understand the DUP's position, but the fact remains that eight unionist members and two SDLP doesn't reflect the make-up of Northern Ireland."
The board's "detachment and authority are unique in policing terms and it would be wrong to upset it now", he added.
Denying the announcement was politically motivated, he said: "It is not being done for Sinn Féin. I believe it will point the finger at Sinn Féin and increase pressure on them to provide proper representation of the constituency. There is no other agenda here other than good policing in Northern Ireland."
Mr Bradley said he will not seek appointment to any new board when it is finally reconstituted.
The SDLP's Alex Attwood, another board member, said: "The decision to continue the present membership of the policing board until October 2006 is the right decision for policing."
Ulster Unionist leader Sir Reg Empey said: "We are opposed to this roll-over. This decision by the secretary of state, who has clearly been influenced by both Sinn Féin and Dublin, is specifically designed to make it easier for Sinn Féin to join."