After the landmark vote at the Sinn Fein ard fheis in Dublin, Mr Paisley said republicans must now "walk the road" of supporting law and order.

He said: "No post-dated action can take the place of real delivery. The postponements must come to an end.

"The time for true, visible and open support for the police and law enforcement has arrived. This shift means telling police about crime, taking seats on accountability bodies like the Policing Board and District Policing Partnerships.

"Only with real delivery can the way be cleared for a full return to democracy and a facing up to the everyday needs and requirements of the people of Northern Ireland.

"The site must be cleared before proper building can begin. All Ulster people, across both the religious and political divides, know that it is now or never."

But SDLP leader and Foyle MP Mark Durkan praised Sinn Fein's historic decision and urged the DUP to support power-sharing.

Mr Durkan said: "I welcome Sinn Fein's decision and I hope that it means they will soon be joining the rest of us in inclusive policing structures.

"But I also want the DUP to allow us all to go forward in inclusive political structures."

Ulster Unionist Party leader Sir Reg Empey said it was a "tragedy" it had taken so long for republicans to support the rule of law and order.

In statement issued shortly after the results from the Sinn Fein ard fheis were revealed, Sir Reg said: "The UUP has been saying for months that Sinn Fein had nowhere else to go as they had to sign up to the Pledge of Office to support law and order before joining any future Executive.

"But the tragedy is that it has taken republicans so long to wake up to change and play their last card. They have used this card as leverage and Government has run, bent over backwards and offered sweetener after sweetener to them when there was no necessity to do so in order for them to show their hand.

"The move is a massive step change in the republican psyche. It is an admission that the violent 'cause' has been abandoned and that Sinn Fein are prepared to support the forces of law and order in this part of the United Kingdom.

"The people of Northern Ireland want progress and they want to move on. Today's vote is a critical piece of the jigsaw in getting the much needed devolved institutions back up and running.

"It is also important today to recognise the tremendous debt our society owes to the service and sacrifice of the RUC and other security forces."