Martin McGuinness phoned the man who was publicly known as the most senior agent inside the IRA to ask for advice about the Good Friday Agreement talks, according to former UUP leader Lord David Trimble.
Lord Trimble told the News Letter that Sean O’Callaghan, the former Southern Commander in the IRA who had come out as a senior Garda agent, disclosed the information while working as his advisor in the late 1990s.
Mr O’Callaghan, 62, drowned in a swimming pool in Jamaica this week while visiting his daughter.
The County Kerry native joined the IRA while a teenager in the 1970s and rose through the ranks to become Southern Commander. However he later came to believe the IRA was driven by sectarianism and began to work for the Garda as an informant.
Mr Trimble said Mr O’Callaghan had been an advisor to him in the Good Friday Agreement (GFA) talks era.
“What he was able to do was to give us some insight into the way in which the republican leadership worked, which of course he had a considerable insight into,” he said.
He added: “There was one quite amusing aspect of all this. It was an occasion we were not getting on well with the republican leadership and we were insisting on them doing things, and they were accusing us of not wanting to reach agreement.
“And late one night Sean got a phone call. And the other side of the phone call was Martin McGuinness. And there was no love lost between those two.
“And McGuinness phoned up and said: ‘Is Trimble really serious about working this agreement?’ And of course, Sean said ‘yes’.
“But of course in those days the republican movement were still trying to kill Sean.”
Asked why he thought Mr McGuinness made the call, he said: “You have no idea what was in his mind, except that there must have been – obviously – an element of doubt and ‘we will see what we hear there’. We have no idea what their response was to what they heard.”
Sinn Fein did not offer any comment yesterday.
The peer dismisses claims Mr O’Callaghan exaggerated his role in the IRA, noting: “The Irish authorities said many times afterwards he was the most valuable agent they had”.
He added: “He was intelligent and incredibly brave to do what he did.
“And one of the drivers was his conscience and the need that he felt to do as much as he could to damage the republican movement and to try and dissuade young people from being drawn into the same evil game.”
Historian Lord Paul Bew, also a former Trimble advisor, had been friends with Mr O’Callaghan since 1998.
In recent years, he said, Mr O’Callaghan made many Muslim friends and was planning a book on extremism, and also worked with young Londoners to counter knife crime.
“I remember speaking with a very senior Irish official who fully accepted the good that Sean had done for the [Irish] state,” he said.
“However he said he did not want to hear from him again. The feeling in Irish culture is so strongly against the informer.”
He added that Mr O’Callaghan privately reassured the Orange Order that the GFA would stabilise the Union while also persuading Tony Blair to respectfully address the Order’s concerns about the deal.
Dean Godson, director of the London-based think tank Policy Exchange, another friend of Mr O’Callaghan’s, said some obituaries wrongly painted him as “a darling of the Tory right” although he did have friends among them.
“Sean was classless,” said Mr Godson, who spoke to him by phone the night before he died. “He had a range of friends at all levels of British society – and with all shades of opinions.”
He added: “He was very driven and had a tremendous sense of duty. Every week was a hard week for him, with a sense of trying to improve things and battle for the cause he believed in.”