A secret peacemaker who brought the British government and the IRA together to help end the Troubles should have received the Nobel Prize, his funeral service was told.
Brendan Duddy (80) worked tirelessly for 20 years and took risks to create trust and the conditions for dialogue, mourners were told. The businessman was a back channel contact between republicans and the state throughout the worst of the Troubles.
The clandestine connections - at a time when British public opinion would not tolerate talking to terrorists - led to the IRA's 1994 ceasefire and the Good Friday peace agreement four years later.
Veteran broadcaster Peter Taylor paid tribute at Mr Duddy's Funeral Mass in St Eugene's Cathedral in Derry.
He said: "Brendan's contribution is incalculable.
"John Hume and David Trimble deserved the Nobel Peace Prize, but Brendan Duddy deserved it too.
"We owe him a great debt."
After the Bloody Sunday shooting dead of civil rights protesters by soldiers in 1972 in his native city, Mr Duddy met an MI6 officer called Michael Oatley and became the secret channel between the British government and the IRA that would last until the 1990s.
He was the key link between then-prime minister Margaret Thatcher and the IRA during the 1981 hunger strikes.
In the early 1990s, he held talks at his own home in Derry between Mr Oatley, the intelligence services, and late Sinn Fein leader Martin McGuinness and the republican leadership.
Fr Chris Ferguson said: "Brendan's role was to help people see the opportunity that existed for peace."
Presbyterian minister David Latimer also paid public tribute to Mr Duddy's peacemaking efforts for and urged people in Northern Ireland to work together before it is too late.
He said: "We have suffered together and felt pain together, we now need to move forward together - for we all belong to this place.
"There can be no going back because we have come too far. Work together before it is too late."
During the Troubles, First Derry Presbyterian Church was frequently a target for attack; sometimes missiles were launched from the other side of Derry's historic walls and paint bombs thrown.
Mr Latimer has been a conciliatory figure in Derry and has spoken openly about his friendship with late Sinn Féin leader Martin McGuinness.
The chief mourners were Mr Duddy's wife Margo, children Patricia, Lawrence, Paula, Brendan, Shauna and Tonya and wider family.
Mr Hume, former Foyle MP Mark Durkan and a representative of President Michael D Higgins attended.
His former running team, the City of Derry Spartans, formed a guard of honour as he was brought from the church.
Fr Ferguson said Mr Duddy was able to help diverse groups identify how peace might evolve.
"Brendan worked hard at creating trust, ensuring that there would be no disclosures that could have harmed the building of relationships.
"He firmly believed there was a willingness on all sides to negotiate."
At the beginning of tentative talks, people could be asked to stoke the fire or some other job as an ice-breaker.
The priest added: "This informal, low-key diplomacy seemed to be Brendan's forte - he was able to build trust.
"Brendan had a great ability to think outside the box which was so necessary in the infancy of the political discussions in which he was involved.
"Always maintaining the long view, Brendan never gave up hope, regardless of many setbacks."
He said: "Brendan in his position as a facilitator found himself bearing witness to the secret fears and anxieties of all sides, containing this tension became a life-long vocation with the aid of all those who were involved in the secret talks, with those who managed to keep the back channels open."
The priest said he had an intuitive ability to understand people.
"Being a husband and father Brendan had a vested interest in seeing an end to the conflict through real and meaningful negotiations."