Sinn Fèin's expulsion of Denis Donaldson, who the party has alleged is a British spy, has been described as "bizarre" by Taoiseach Bertie Ahern.
Speaking from the EU summit in Brussels Mr Ahern said the dismissal of Mr Donaldson - long-standing member of the party and Sinn Féin's former head of administration at Stormont - was as "bizarre as it gets".
Mr Donaldson was arrested at Stormont when the spy ring affair broke in October 2002. The affair led to the fall of the Assembly and Executive, but charges were dropped by the North's Public Prosecution Service (PPS)earlier this month.
Mr Ahern said that he would broach the subject with Prime Minister Tony Blair. He admitted in the RTEinterview that 'Stormontgate' "never made much sense" to him, and said he would wait until he heard all sides of the story before commenting further.
The Northern Ireland Office responded to the news by insisting that there was never any other reason for police raids on Sinn Féin offices in 2002 other than to "prevent paramilitary intelligence gathering".
A statement issued this evening read: "The fact remains that a huge number of stolen documents were recovered by the police.
"As a result of the recovery of these documents, a large number of people had to be warned.
"We are not going to comment on the specifics of the case or these allegations.
"In terms of the dropping of the prosecution, that was a matter for the independent prosecuting authorities and there was no political interference whatsoever in that decision."
Close associates of Mr Donaldson in Sinn Fèin admitted there was astonishment in the republican ranks at today's dramatic twist. "Normally touts are hateful bastards but Denis is a likeable guy," one republican source said. "People really are in shock."
In recent days, unionists and moderate nationalists at Westminster have pressed Mr Blair, Attorney General Lord Goldsmith and Northern Ireland Secretary Peter Hain for a Parliamentary statement explaining why the Public Prosecution Service withdrew the court case involving Mr Donaldson.
Following today's sensational twist, those calls grew even louder. Nationalist SDLP deputy leader Dr Alasdair McDonnell said: "We suspected that the public interest argument was a way of covering up for an informer.
"We don't know whether Denis Donaldson was that particular informer.
"There is the distinct possibility, like so many cases in the past, that he is being used as a scapegoat to cover someone else.
"There is now deep scepticism about what goes on in elements of the British Government and the Provisional leadership.
"The British Government cannot retain credibility and continue to duck behind smokescreens called public interest."
The Democratic Unionists also called for a detailed Government statement on the affair.
In a statement the Rev Ian Paisley's party said: "It is now time for a full and detailed explanation from the Government and for them to explain whether this the reason for the dropping of the charges against those accused.
"If not, why was the decision taken by the DPP?"
Ulster Unionist leader Sir Reg Empey also asked for an immediate meeting with British officials to discuss the affair which has the capacity to embarrass the intelligence services and the judiciary.
"If this was the person who was being protected by the DPP, then there is no reason why these prosecutions cannot proceed," the former Stormont Economy Minister said.
"It actually debunks the claims by Sinn Fein there was no spy ring operating inside Stormont, when in fact there was," he added.