All political parties in the United Kingdom must be funded by "purely democratic and peaceful methods", the Prime Minister Mr Tony Blair insisted today.
He was responding to a claim at House of Commons question time that Sinn Féin was being funded by criminal activity organised by the IRA.
The UUP MP for South Antrim, Mr David Burnside told Mr Blair that "very serious allegations had been made that political parties like Sinn Féin are being funded by the Provisional IRA through criminal activity".
He asked: "Will you join with me in making the UK law uniform and applying the same legislation to Northern Ireland on the funding of political parties as applies in the rest of the UK."
Mr Blair responded: "Any criminal activity of the sort you describe is completely unacceptable.
"We cannot have a situation were people are expected to sit in government with political parties attached to active paramilitary organisations."
In the course of the review of the working of the Belfast Agreement, it was important to make clear that "there cannot be a situation in which a political party is being funded by anything other than purely democratic and peaceful methods".
This evening, Sinn Féin MP Ms Michelle Gildernew denied the allegations. "The Sinn Féin accounts are all properly audited and adhere to all the guidelines set out in both the six and 26 counties," she said. "The Standards in Public Office Commission have recently confirmed as much.
"As for Mr Blair it would be more appropriate if he addressed the many outstanding commitments which he has breached, including his failure to publish or act upon the Cory Report, than become the cheer leader for the UUP rejectionist wing each Prime Minister's question time."
Last week, the Fine Gael leader Mr Enda Kenny called for an investigation into Sinn Féin's source of funds after the Minister for Justice, Mr McDowell, said there was substantial evidence that the IRA was still involved in criminal activity.