Sinn Fein has been accused of "running scared" on the issue of policing in Ulster, four years after the Patten Commission published its recommendations.

Speaking on Friday Alex Attwood, chairman of the SDLP, argued that the reforms, under which the Police Service of Northern Ireland replaced the Royal Ulster Constabulary, had been a success.

"It is four years since Patten and only two years since the policing board was established," he said.

"The pace of policing change continues to accelerate, despite the joint efforts of unionists who resist Patten and Sinn Fein who fail to join in the work of implementing Patten.

"A brief review of the last two years confirms the range of progress - a new name, badge and flag."

Attwood also pointed to such changes as the appointment of Hugh Orde as chief constable, equal recruitment levels between protestants and Catholics, and the vindication of the ombudsman's report into the Omagh bombing.

"Challenges endure but change is irreversible," he said.

A member of the policing board, Attwood claimed that Sinn Fein was running out of excuses for not endorsing the new force.

"Sinn Fein have long ago run out of reasons and now rely on lame excuses for failing to join the board and the district policing partnerships," he said.

He called on the British and Irish governments not to "allow the further evasion by Sinn Fein of their political and policing responsibilities".

"The resolve of those working to implement Patten has been most graphic this week," he added.

"The resilience and strength of DPP members is powerful testimony of the commitment of crowing numbers to changed and better policing.

"This week has demonstrated that those who have failed to take up the Patten challenge are out of date, out of touch and running out of time."