A judge will be appointed to investigate the operation of a government scheme to deal with on-the-run republicans, British prime minister David Cameron has announced.
Mr Cameron said he accepted calls for a "full, independent examination" of the process after Democratic Unionist First Minister Peter Robinson threatened to resign.
Details of 187 letters sent to so-called on-the-run republicans (OTRs), assuring them that they would not be prosecuted if they returned to Northern Ireland, emerged when a case against a man charged with the 1982 IRA Hyde Park bomb collapsed.
“I agree with the First Minister of Northern Ireland that, after the terrible error in the (John) Downey case, it is right to get to the bottom of what happened,” Mr Cameron said. “The case has already been referred to the Police Ombudsman but, as the First Minister has said, we should have a full, independent examination of the whole operation of this scheme.
“So I can announce today that we will appoint an independent judge to produce a full public account of the operation of this administrative scheme to determine whether any other letters were sent in error.”
The judge will be given “full access to government files and officials” and will report by May, Mr Cameron said, with the findings being published.
Earlier, Sinn Féin Deputy First Minister Martin McGuinness claimed Mr Robinson’s threats to collapse the Stormont administration were an attempt to distract from the fact they knew the process existed.
“I think Peter is well aware of my view that this is a time for steady leadership, this is a time for calm nerves, this is a time for solutions to the present scenario we find ourselves,” he said. “This is certainly not the time - though I don’t fear it at all - for an election.”
Mr McGuinness said he would never voluntarily walk away from the devolved institutions.
"I will never resign," he said after meeting Northern Ireland Secretary Theresa Villiers to discuss the issue.
DUP claims that it was unaware of the deal between the British government and Sinn Féin on OTRs have been questioned after it emerged that a senior Police Service of Northern Ireland (PSNI) officer briefed members of the NI Policing Board on elements of the scheme in 2010, albeit without mention of the letters.
DUP members were present at the Policing Board meeting. The issue was also mentioned in the high-profile 2009 Eames-Bradley report on dealing with the legacy of the Troubles.
Mr McGuinness said: “I think that the angst among unionist politicians is more centred around the common belief out there in society and in the media that they knew all about this.
“They may not have known about the letters, but they knew about the scheme and they knew that these people who were described as on-the-runs were being processed.
“I think that’s where the annoyance comes from.”