Speaking at a press conference in Belfast, Sinn Fein councillor Alex Maskey said: "If the RUC remains, then the agreement has failed and we're back to the drawing board, particularly on issues like policing."

He said if a major section of the Stormont agreement, such as policing, did not work it would be deemed a failure by many people.

Sinn Fein also raised the prospect of former IRA terrorists joining a new police force which it said would replace the RUC.

Mr Maskey added: "There are people in our community who are entitled to be and should be part of any new police service, whether ex-members of the IRA, ex-prisoners or ex-RUC officers."

The RUC is seen as a "unionist militia" by republicans

He insisted senior RUC officers must go and said they had been guilty of "systematic human rights abuses".

Policing is one of the most sensitive aspects of the peace process, with unionists fiercely defending the record of the RUC and warning against any moves to abolish it or integrate republican paramilitaries into it.

Republicans on the other hand remain deeply suspicious of the RUC, which is overwhelmingly Protestant, while Sinn Fein sees it as a "unionist militia".

The UK Government announced the membership of the new Independent Commission on Policing, headed by the former Governor of Hong Kong, Chris Patten, on Wednesday.

The commission has been given the task of creating a service which is acceptable to both communities.

But Mr Maskey insisted the RUC would have to go and said: "The remit of the Commission is clear cut. Their task is to establish a police service that and enjoy widespread support from and is seen as an integral part of the community as a whole.

"The RUC cannot achieve that objective. A new police service can."

Last week the Northern Ireland Secretary, Mo Mowlam, said there was no way former republican or loyalist paramilitaries would be allowed to join the police force.