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 March 2009.
The same court ruled yesterday that the convictions against the Co Derry man for murders of sappers Mark Quinsey, and Patrick Azimkar were unsafe.
After the Public Prosecution Service applied for a new trial for the 47-year-old the three Appeal Court judges said it was in the public interest for them to grant the request.
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.
Earlier, applying for a retrial, Crown barrister Terence Mooney QC said Shivers still had a case to answer.
Shivers's 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 this afternoon to deal with a bail application by Shivers's legal team and set a date for the new trial.