The West Belfast man Fred Scappaticci has again denied he was the British Army agent inside the IRA known as Stakeknife.
In an interview given at his solicitor's office in West Belfast this afternoon, he said he was not guilty of any of the allegations made about him in weekend reports and confirmed he had never left the North.
He said he had become aware of the situation on Saturday night but did not know why he had been labelled.
Mr Scappaticci also said he had been involved in the republican movement thirteen years ago but had had no involvement since.
In a statement from his solicitor Michael Flanigan, he also threatened legal action over the allegations that he had operated as a spy.
The SDLP leader Mark Durkan called for a full public judicial inquiry into the activities of British intelligence units in the North following the latest allegations about the agent known as Stakeknife.
Mr Durkan said the case raised a number of key questions such as who had monitored and sanctioned the agent's actions, and how far up did the collusion go.
He asked whether approval for the agent's operations had been sought at Cabinet level and in what terms.
Mr Durkan asked what had been the involvement of the security service, MI5.
He said an enquiry must also answer how many killings did Stakeknife and Brian Nelson, the agent in the loyalist UDA, participate in.
He asked whether Stakeknife had been allowed to deflect attention form himself by getting others killed.
Mr Durkan called on the Canadian Judge investigating allegations of collusion, Judge Cory, to publish the report he had completed on the Pat Finucane case now.
He said there should be no role for MI5 in domestic intelligence gathering in the North, and that British military intelligence should be withdrawn from all activity in the North, especially the Force Research Unit, which has since been renamed.
Commenting on the alleged activities of the British agents, he said the fact was that these people were colluding in and complicit in the most foul breaches of law and order and in the most murderous deeds that could be carried out, and that was where his party was centring its questions.
The North's Security Minister earlier said the British government would co-operate with Sir John Stevens and his inquiry team if he decided to interview the alleged IRA informer known as Stakeknife.
However, Jane Kennedy refused to comment on speculation on the whereabouts and identity of the alleged agent or on arrangements for his safety.
The Minister was replying, during a special debate at Westminster, to calls by Labour backbench MP Kevin McNamara that the British government should put an end to what he described as the uncertainty over the position of Stakeknife.
Kevin McNamara said no impediment should be put in the way of Stakeknife's interrogation by Sir John Stevens' team.
Ulster Unionist leader David Trimble defended the use of covert agents and added that penetration of paramilitary organisations was sometimes necessary to obtain intelligence.