All four members of the North's ceasefire watchdog, the Independent Monitoring Commission (IMC), were today urged to quit after one of them stood down from a political party.
Sinn Féin MP Conor Murphy, whose party has been preparing a legal challenge to have the IMC declared unlawful, made the demand after John Alderdice resigned from the cross-community Alliance Party, which he once led.
In a letter to Sinn Féin's solicitors last Friday, lawyers acting for the former Northern Ireland Assembly Speaker said that while Alderdice did not believe in the public's mind he was perceived as being biased against Sinn Féin, he had quit the Alliance Party to put the matter beyond doubt.
Mr Murphy, however, insisted the setting up of the IMC was in breach of the 1998 Good Friday Agreement and he accused the commission of being a tool for elements opposed to political change.
``It is not and never has been independent,'' the Newry and Armagh MP insisted.
``It is politically biased, has a clear anti-Sinn Féin agenda, and its procedures are flawed.''
Sinn Féin lodged papers in the High Court in London last December to have the IMC overturned.
The commission was set up in January 2004 to report on the state of republican and loyalist paramilitary ceasefires and moves to scale down security in the North.
The Government penalised Sinn Féin twice following IMC reports, withholding Northern Ireland Assembly and Westminster allowances from the party.
The loyalist Progressive Unionists have also been punished by the Government following an IMC report.
The IMC's three other members are former Metropolitan Police anti-terrorism chief John Grieve, retired Irish civil servant Joe Brosnan and ex-United States Central Intelligence Agency deputy director Richard Kerr.