Sinn Féin should get off the fence and encourage Catholics to join the police force in Northern Ireland, European Commissioner Mr Chris Patten said today.
He said republicans must step forward and show their commitment to democracy and fair policing for all.
Sinn Féin has said it will not take its seats on the cross-party policing board, which oversees the force, until the Patten proposals for reform of the service are implemented in full.
However, Mr Patten, the author of the report, said he was satisfied all his recommendations were being put in place.
"I think the Patten Report is being implemented in full and I think that they (Sinn Féin) should get off the fence and support the police service in Northern Ireland and take their responsibilities," he said.
"I find it interesting that, given where they started from, they are now arguing that it's got to be Patten and the whole of Patten or nothing. I take that as a sort of compliment.
"I think that they should support the police service and they should encourage young Catholic men and women to join the police service."
Mr Patten said Sinn Féin had to make their dedication to solely democratic means clear if security and justice matters were to be devolved to the Stormont Assembly.
"You can't go on playing the ballot box with one hand, while the other hand is behind your back, you've got to show both hands," he said.
"You've got to commit yourself fully to the democratic process and you've got to commit yourself fully to decent policing in the interests of the whole community.
"I think that they can't have it both ways; either they are in favour of decent cross-community policing or they are not," he added.
The former Conservative MP defended the current 50-50 policy of recruiting Catholics and Protestants to the Police Service of Northern Ireland despite criticism from unionist politicians.
He said the previous 93% Protestant make-up of the service was indefensible in a force that was expected to be acceptable to the whole of society.
"I think it was essential to try to redress that imbalance in a way which is as fair as possible," he said.
Sinn Féin justice spokesman and North Belfast representative Mr Gerry Kelly dismissed Mr Patten's calls for his party to join the Policing Board.
"We will endorse policing when we get it right," he said.
"The best guarantee that we will get the new policing promised is to confirm
and increase the Sinn Fein mandate in this election."
