The British Prime Minister has apologised to the three men and one woman known as the Guildford Four who were wrongly convicted of IRA bomb attacks in England in 1974.
Mr Blair acknowledged the miscarriage of justice in the case of the innocent four and said he was "very sorry" that they were wrongfully imprisoned.
Details of the apology will be revealed in two episodes of BBC Northern Ireland's Spotlight programme entitled "Capitol Hill", on the changing fortunes of west Belfast man, Mr Paul Hill, to be broadcast on June 6th and 13th.
Mr Hill, Mr Gerry Conlon, Mr Patrick Armstrong and Ms Carole Richardson were given life sentences for bombing public houses in Guildford, Surrey.
Each spent 15 years in prison before the convictions were overturned by the Court of Appeal in 1989, when it emerged the Surrey police had concocted evidence against them and misled the original trial by lying.
The apology, personally signed by the Prime Minister, was sent by Mr Blair to Mr Hill's wife, Ms Courtney Kennedy-Hill, the daughter of the assassinated US attorney general, Mr Robert Kennedy, and niece of the late President John F. Kennedy.
The Prime Minister said: "I believe that it is an indictment of our system of justice and a matter for the greatest regret when anyone suffers punishment as a result of a miscarriage of justice. There were miscarriages of justice in your husband's case, and the cases of those convicted with him. I am very sorry indeed that this should have happened."
It is understood Mr Hill (45) has received £200,000 as an interim compensation payment, and is waiting for a final settlement. He said: "No one knows the monetary value you can put on 15 years. I don't think there is anybody alive who can come out of that experience and not be scarred. Those who would begrudge me my compensation, their minds are smaller than peas. To those who say `Oh, he's living well', you have no idea."
The programme also reveals Mr Hill's friendship with the President of Tuscany, Mr Vannino Chiti, who was at the centre of a controversy last year when he hosted Mr Blair's family holiday.