Northern Ireland Assembly members will today debate the status of the IRA ceasefire with First Minister Mr David Trimble calling on Northern Secretary Dr John Reid to take action against Sinn Féin.
A motion tabled by Mr Trimble has called on Dr Reid to make an assessment of the IRA's ceasefire amid allegations the group is targeting leading Conservatives and was behind the March 17th break-in at the top security Castlereagh Police Station.
Mr Trimble said today Dr Reid should assess whether the IRA ceasefire had been broken and, if he ruled it had, Dr Reid could take action under the prisoner release legislation.
If Dr Reid failed to do this, unionists would be left only with the "nuclear option" of bringing down the Belfast Agreement altogether, Mr Trimble told the BBC Radio 4 Todayprogramme.
"It is [Dr Reid's] duty to act in the public interest in this matter and maintain the integrity of the process. It shouldn't be left to us, because unfortunately the only weapon we have is one which would destroy the whole process.
"If the Government wants this process to succeed, the Government has a responsibility to act, because we want to see the agreement fulfilled in terms of delivering peace and democracy to the people of Northern Ireland. John Reid is obstructing that at the moment through his failure to act," Mr Trimble said.
A hardline member of Mr Trimble's Ulster Unionists called on colleagues to use the motion as a prelude to a series of sanctions against Sinn Féin.
South Antrim MP David Burnside said hoped the motion would "signal the beginning of the end of Sinn Féin being in the government of Northern Ireland.
"Sinn Féin have carried out a monumental con job since 1998 - pretending to be a democratic party whilst being directly involved in international terrorism in Colombia, maintaining a fully armed legal terrorist army and carrying out extensive criminal activities in the province," he said.
PA