Northern Ireland's First Minister Peter Robinson lifts threat to resign over controversy about on-the-run Irish republicans.

Peter Robinson had threatened to quit if there was no review of the guarantee given to suspected Hyde Park bomber John Downey that he will not face prosecution.

Downey (62) received a letter of assurance from the Northern Ireland Office of the British government which led to the collapse of a case against him this week.

Mr. Robinson said he was "kept in the dark" by the British government.

"I have to say quite frankly that I am not prepared to be the First Minister of a government that is kept in the dark on matters that are relevant to what we are doing" he said.

"That is not acceptable to me. I want to have a full judicial inquiry into who knew what, when they knew it and exactly what they did know at the time. I also want to ensure that the letters that have been sent out are rescinded" he added.

John Downey walked free from court on foot of an immunity deal

The British Prime Minister David Cameron today described the case as a "dreadful mistake" and said it was "absolutely shocking".

He also called for a review into why the letter - which wrongly stated that Downey was not being sought by British police - was sent.

Convicted IRA member Downey, from Donegal, had an outstanding warrant against him when he received the letter in 2007. The attack killed four people in July 1982.

The families of the victims have said they feel "devastatingly let down" by this week's developments.

Nothern Ireland Secretary Theresa Villers said it's important to get a full account of how this scheme operated: