Gerry Conlon, who was wrongly convicted over Guildford pub bombings in 1974, has died aged 60.
Mr Conlan, who was 60 and had been ill for some time, died this morning at his home off the Falls Road in west Belfast.
The Guildford Four — Gerry Conlon, Paul Hill, Carole Richardson and Paddy Armstrong — were jailed for life in 1975 for an IRA bombing campaign which killed five people and injured 65.
Mr Conlon's father, Giuseppe, was jailed later that year. He died in prison five years later.
Giuseppe was jailed as part of a discredited investigation into a supposed bomb making family - the Maguire Seven.
Giuseppe had one lung, and emphysema and had just undergone chemotherapy.
His mother Sarah, a tireless campaigner for their freedom, died in 2008, aged 82.
The Guildford Four were freed in 1989.
In 2005, sixteen years after their release, Tony Blair delivered a public apology to the Conlon and Maguire families, saying they deserved to be completely and publicly exonerated.
In a statement Mr Conlon's family said: "This morning we lost our Gerry. He brought life, love, intelligence, wit and strength to our family through its darkest hours.
"He helped us to survive what we were not meant to survive.
"We recognise that what he achieved by fighting for justice for us had a far, far greater importance - it forced the world's closed eyes to be opened to injustice... we believe it changed the course of history.
"We thank him for his life and we thank all his many friends for their love."
Alex Attwood, SDLP MLA for West Belfast said:"On my own behalf and that of the SDLP, I extend deep sympathy to Gerry's partner and his family. May he rest in peace with his late parents.
"He was a big character. Gerry made a big and lasting impression on all those he met. He had a great resilience, an incredible warmth and a huge heart.
"He also had a deep commitment to justice and democracy. He stood with all those who had been denied their rights and suffered wrong.
"The miscarriage of justice perpetrated against him, his dad and his friends was shocking. The campaign of Gerry and others concentrated a spotlight on the wrongs of the State like never before. His eventual release was very significant in itself, was also a catalyst for campaigns against other miscarriages of justice.
"Gerry will be missed as a person and missed for the vigor and support he brought to other campaigns for justice. His death at 60 years of age is far too young for someone who had suffered far too much, who had then given so much and had so much more to give”.
Mr Conlon's case was highlighted in the 1993 Oscar-nominated film In The Name Of The Father, starring Daniel Day-Lewis.
Sinn Fein president Gerry Adams expressed his shock and deep sadness at the news.
"Gerry and his father Giuseppe were two of the most infamous examples of miscarriages of justice by the British political and judicial system," Mr Adams said.
"Their story was told graphically in the film In The Name Of The Father. To his family and friends I want to extend my sincere condolences."
In 2009 Mr Conlon wrote about the personal and emotional battles he suffered as a result of his incarceration and fight for freedom.
He suffered two breakdowns, attempted suicide and became addicted to drugs and alcohol following his release.
Mr Conlon also only began enduring nightmares after securing freedom.
"The ordeal has never left me," he said.
Miscarriage of justice
The jailing of Conlon and the other members of the Guildford Four - Paddy Armstrong, Paul Hill and Carole Richardson - is considered the biggest miscarriage of justice in British legal history.
They were jailed for life in 1975 for the devastating attack on the Horse and Groom pub in the Surrey town which killed four soldiers and a civilian.
But they were freed in October 1989 after the Court of Appeal quashed their sentences amid doubts raised about the police evidence against them.
An investigation by Avon and Somerset Police found serious flaws in the way Surrey Police handled the case.
As he emerged free from the Court of Appeal Gerry Conlon declared: "I have been in prison for something I did not do. I am totally innocent."
Paddy Hill – one of the Birmingham Six – was wrongly jailed for 17 years for similar crimes.
Both men had accused the Government of "washing their hands" of innocent Irish men and women who, according to Mr Conlon and Mr Hill, have either been framed or are currently rotting in jail.
Speaking at the University of Limerick earlier this year, Mr Hill said: "If what happened to us meant that no other innocent people were going to go to jail, in some way we could accept it – but unfortunately, it's not that way.
"More and more innocent people are going to prison. I don't know how many are presently (before) the Criminal Cases Review Commission in England and Scotland (but) it's just a ridiculous situation," Mr Hill added.
Mr Conlon said at time that he believed powerful organisations like MI5 are involved in a "dirty tricks" campaign against certain people.
Advocating on behalf of people who claim to be victims of miscarriages of justice, Mr Conlon and Mr Hill said lessons needed to be learned from how they were treated by the British judicial system.
"We need accountability, we need transparency and we need accessibility to the judiciary and they need – when things go wrong – to be told the truth."
Although the scandals of the Guildford Four and Birmingham Six cases have been known for more than 30 years, they have been denied full access to the entire case files.
"We are the only two cases in British criminal history where the Official Secrets Act has been applied. It was recommended that our cases be held under the Official Secrets Act for 75 years. That's longer than the secrets from the Second World War."
Mr Conlon had said that he was no longer bitter but admitted he was still angry at what had happened to him and Paddy Hill.