Bricklayer Seamus Daly has been released from prison after his prosecution for the Omagh bomb attack collapsed before it reached trial.
The case against Mr Daly, who was charged with murdering 29 people in the 1998 Real IRA outrage, was dropped in court on Tuesday morning.
Mr Daly, 45, had been on remand in prison since being charged with the atrocity and a range of other terror offences in April 2014.
The Co Armagh man walked free from Maghaberry high-security prison in Co Antrim just before 3pm, declining to make public comment before being driven away by family members.
Seven years ago, Mr Daly was one of four men successfully sued for bombing theCo Tyrone market town when he was found liable for the attack in a landmarkcivil case taken by some of the bereaved families.
No-one has ever been convicted of the murders in a criminal court.
Michael Gallagher, whose son Aiden was killed in the bomb, was in Ballymena Magistrates’ Court when the decision to drop the case was announced by a barrister for the Northern Ireland Public Prosecution Service.
“Here we are again after 18 years. Extremely disappointed,” he said afterwards.
“We’ve been let down by the police service, by the PPS, by the criminal justice system.
“And this is probably, or was probably, the last chance for justice.
“Unfortunately now that’s not going to be the case. We’ll have to re-evaluate and discuss with our legal team what the best way forward is.”
Mr Daly, from Co Armagh, has always denied involvement in the bombing which inflicted the greatest loss of life of any terror atrocity in the history of the Northern Ireland Troubles.
The dead came from both sides of the Irish border, England and Spain. One of the victims was pregnant with twins.
The dramatic decision by PPS came before Mr Daly’s case had even reached the floor of the Crown Court.
A pre-trial hearing commenced in Omagh Magistrates’ Court last week to establish whether the evidence in the case was of sufficient strength to warrant such a trial.
That decision was taken out of District Judge Peter King’s hands when the PPS withdrew the charges before the preliminary hearing had reached conclusion.
As well as the 29 murder counts, Mr Daly, from Kilnasaggart Road, Jonesborough, Co Armagh, had faced charges of causing the August 1998 explosion and possession of a bomb with intent to endanger life or property.
He was further charged with conspiring to cause an explosion and having explosives with intent in connection with a separate dissident republican bomb plot in Lisburn in April of the same year.
All charges have now been dropped.
In 2009, Mr Daly and three others were ordered to pay £1.6 million in damages to the bereaved relatives – money they are still pursuing.
Mr Daly faced a civil retrial after successfully appealing against the original finding, but the second trial delivered the same outcome as the first, with judge Mr Justice John Gillen ruling him responsible for the attack.
In 2007, south Armagh electrician Sean Hoey, who was then 38 and from Jonesborough, was found not guilty of the 29 murders after a marathon trial at Belfast Crown Court.
At the time, trial judge Mr Justice Weir heavily criticised the Royal Ulster Constabulary and its successor, the Police Service of Northern Ireland, for their handling of the investigation.
The decision to drop the case came after inconsistencies emerged in the evidence of a key prosecution witness, Kilkenny builder Denis O’Connor, during the pre-trial hearing.
His testimony had been subject to reporting restrictions until the charges were dropped.
Mr Gallagher said he regrettably agreed with the PPS decision.
“This was a difficult case and hinged on the testimony of one individual and that one individual did not seem to be up to meeting the test needed to put someone behind bars,” he said.
“For that reason I agree with the decision, regrettably, that happened today.
“There was no other option for the Public Prosecution Service or the judge but to deliver the verdict that we have just heard.”
A spokeswoman for the PPS said: “On behalf of the PPS, I extend our sympathy to the families affected by the Omagh bomb.
“We understand how difficult this decision will be for them. We hope they are assured that this decision was not taken lightly but is required in accordance with our duty as prosecutors to keep a decision under review and to discontinue criminal proceedings when the Test for Prosecution is no longer met.”
Family and friends who had been campaigning for Mr Daly’s release said he had been “interned” for 23 months.
A statement from the Release Seamus Daly group said: “The case against Seamus Daly has been flawed from the beginning. The British Government along with the prosecution proceeded against Seamus with no tangible evidence.”
Mr Daly’s solicitor, Peter Corrigan, said his client had been held in custody for a considerable period of time for offences which he vehemently denied.
“The defendant has been in custody for two years – the equivalent of a four-year custodial sentence (allowing for 50% remission) – and this was based on a prosecution house of straw in our view,” he said.
Mr Corrigan said he would support the call for a public inquiry into the bombing.