Northern Ireland's First Minister Peter Robinson has threatened to walk away from government, unless an official inquiry is launched into the controversy surrounding an aborted IRA bomb trial.
The development follows the collapse of a high-profile trial in London, which saw John Downey - the Donegal man who was charged in connection with the 1982 Hyde Park bombing that killed four British soldiers - walk free from the Old Bailey.
After meeting Northern Secretary Theresa Villiers at Hillsborough Castle last night (Wed), the furious DUP leader indicated there would be serious consequences if his demands for an independent probe into the matter were not met.
He said he is outraged that he and other Stormont ministers had not been informed of a secret deal that saw the British government grant immunity from prosecution to an estimated 200 republican 'on-the-runs' (OTRs) over a number of years.
The Irish Times reports that the deal between the British government and Sinn Fein was struck some time after former British Prime Minister, Tony Blair's government failed to bring in legislation in 2005 to deal with the 'anomaly' of the the OTRs.
Convicted paramilataries were released from jail under the Belfast Agreement, but the position of the OTRs remained less clear and led to a vigorous campaign from Sinn Fein for them to be granted immunity.
The political crisis deepened in recent days following the London court's ruling not to try John Downey, 62, after it emerged he was one of the nearly 200 republicans who received so-called 'comfort' letters from the British government, informing them they would not face prosecution.
But speaking after his hour-long meeting with Ms. Villiers, Robinson said he had also learned that royal pardons had been granted to a number of republicans who were wanted in relation to a series of terrorist crimes during the Troubles.
The First Minister has recalled the Northern Assembly tomorrow (Fri) to discuss the deepening political crisis.
And he said the contents of the motion he would put before the Assembly depended on how the British government responded to his demand for a judicial inquiry to be set up.
He said public confidence in the judicial and political process had been badly tarnished and insisted that full transparency was urgently required in relation to the controversy.
He said: "It appears that we are not just dealing with on-the-runs who received letters, but we are also dealing with people who received the Royal Prerogative of Mercy, that indicates there were offences involved.
"So we are not talking just about people who it is believed that the police did not have sufficient evidence to make a prosecution stick - that makes it a very serious matter."
However, Robinson said he was hopeful British Prime Minister David Cameron would respond positively to his demands for an inquiry.
He said: "I am asking for what is necessary and I don't think the Conservative Party is a party that will want to defend or support or hide those who have responsible for terrorism, so I have high hopes that I am not asking for the impossible."
The escalating crisis is reportedly being closely monitored in the Republic of Ireland by Taoiseach Enda Kenny's top officials.