Tributes have been paid to businessman and peacemaker Brendan Duddy, who has died after an illness.
Mr Duddy had been unwell following a stroke some years ago.
He was taken to hospital earlier this week, and died last night at the age of 80 surrounded by his family.
At the height of the Troubles Mr Duddy acted as a go-between between the IRA and the British Government.
He was in regular contact with a senior British intelligence agent Michael Oatley, and relayed messages between the two sides even as the security situation deteriorated.
The back channel established by Oatley and Mr Duddy lasted from the mid-1970s through to the IRA ceasefire of 1994.
Mr Duddy rose from being the owner of a chip shop in Londonderry to being a major businessman in the city.
In an interview with the BBC’s Peter Taylor, he claimed to have first met IRA chief Martin McGuinness when the younger man was delivering burgers to his chip shop.
In later years the work of the two men would be invaluable in bringing the conflict here to an end.
During the 1981 hunger strikes, at a time when Anglo-Irish relations were at an all-time low, Mr Duddy maintained his contact and attempted to get the Government to move before the situation worsened, but Prime Minister Margaret Thatcher thwarted efforts to bring the prison fast to an end. Codenamed ‘The Mountain Climber’, Mr Duddy renewed his efforts.
And in 1991 he was able to bring McGuinness and Oatley together for a face-to-face meeting that proved crucial in the later development of the peace process.
Jonathan Powell, former chief of staff to Prime Minister Tony Blair, claimed if it had not been for contact maintained through Mr Duddy, the peace process might not have been possible.
When it became public knowledge that London had back channel contact with the IRA there was condemnation, including from the DUP leader Ian Paisley.
Powell claimed that later on the DUP had its own back channel with Sinn Fein.
Mr Duddy himself refused to talk about a lot of his work, and his private archives were donated to the James Hardiman Library in the University of Galway.
The historic archive opened in 2011.
Tributes began to emerge on social media after the news broke last night.
Journalist Peter Taylor, who interviewed Duddy about his years as a secret intermediary between the IRA and the Government, said: “He was one of the unsung heroes of the peace process.
“His place in history will be secure.”
Former UUP Stormont minister Danny Kennedy tweeted: “Sorry to learn of the death of Brendan Duddy. I served with him on the NIPB for a brief period. He was a fine and honourable man.”