The Court of Appeal in Belfast has ordered that Brian Shivers face a retrial for the murders of two British soldiers at Massereene barracks in 2009.
The same court ruled on Tuesday that the convictions against Brian Shivers for the 2009 murders of sappers Mark Quinsey, 23, and Patrick Azimkar, 21, outside Massereene army barracks in Antrim were unsafe.
After the Public Prosecution Service (PPS) applied for a new trial for the 47-year-old from Magherafelt, Co Londonderry, the three Appeal Court judges said it was in the public interest for them to grant the request.
Shivers was convicted of the murders at Antrim Crown Courtin in January last year when he stood trial alongside high profile Republican, Colin Duffy, who walked free after being acquitted.
Defence lawyer Patrick O'Connor QC had claimed that a new trial would represent an "abuse of process".
He also argued that his client should have been acquitted at his original trial so a new case against him would effectively be contravening the law of double jeopardy.
But the judges rejected the defence submission, insisting that their decision to quash the original convictions was founded on issues relating to judicial direction.
They said the judge in the new trial could address any concerns over abuse of process.
A bail application for Shivers was refused by the Court.
In refusing bail, the Appeal Court judges acknowledged the health issues facing the cystic fibrosis patient but said the risk of him offending was too high to release him from Maghaberry high security jail in Co Antrim.
Earlier, applying for a retrial, Crown barrister Terence Mooney QC said Shivers still had a case to answer.
He told the three appeal court judges: "We submit it's in the interest of justice that you may order a new trial."
Shivers, dressed in a shirt and jeans, was in court for the hearing.
The English soldiers were gunned down as they collected pizza outside the gates of the barracks. They were just hours away from deploying to Afghanistan.
The Real IRA claimed responsibility for the shootings.
Shivers, who suffers from cystic fibrosis, was ordered to serve at least 25 years by trial judge Justice Antony Hart.
His appeal against additional convictions on six counts of attempted murder and one of possession of two firearms and ammunition with intent to endanger life was also allowed by the Court of Appeal.
He will face a retrial on all original counts.
The court will sit again on Wednesday afternoon to deal with a bail application by Shivers's legal team and set a date for the new trial.