North Belfast woman Christine Connor, who was jailed for trying to murder police officers, has won her appeal against the conviction.
Senior judges ruled that guilty pleas entered by 32-year-old Connor were equivocal and could not be safely regarded as representing genuine confessions.
They quashed her convictions and ordered a retrial over an alleged terrorist plot said to involve posing online as a Swedish model to lure men into supporting the bid to kill.
Connor is to be released on bail pending the fresh hearing on the charges against her.
In June 2017, she received a 16-year prison sentence for attempted murder, possessing explosives with intent to endanger life, causing an explosion, and involvement in preparing terrorist acts.
Charges against her included a role in home-made bomb attacks on police patrols lured to the city’s Crumlin Road in May 2013.
She allegedly placed a hoax 999 call and claimed a woman living in the area was in danger.
Although the grenades detonated in the first attack, no-one was injured.
Twelve days later, one policeman was injured when more bombs were thrown.
At a re-arraignment as she was set to go on trial in May 2017, she replied to each of the charges: “I am not guilty, but on advice, I will plead guilty.”
Connor launched a bid to have her convictions overturned on the basis that the trial judge failed to intervene and examine ambiguities around those pleas.
Giving evidence at the Court of Appeal, she claimed to have acted under immense pressure from her former lawyers.
She alleged that the issue of admitting the charges was first raised at a consultation on the day before her re-arraignment - triggering underlying anxiety disorders.
Connor told the court she was informed that she should plead guilty, leaving her feeling that she was “drowning or suffocating”.
But her former barrister testified that she raised no issue about her legal advice at a meeting in the aftermath of the plea being entered.
He told the three appeal judges she was only concerned with being wrongly depicted as a “lone-wolf terrorist”.
A solicitor who represented her at the time also gave evidence that he understood she planned to plead guilty.
Delivering judgment on the appeal, Lord Justice Treacy identified the alleged ambiguity around her pleas as being the key issue.
He pointed out that in response to the attempted murder charge, Connor had stated she was “most definitely not guilty” but was pleading guilty on advice.
“On any showing, the pleas were highly qualified, ambiguous and equivocal,” the judge said.
Inquiries should have been made before proceeding to sentence, he stressed.
The prosecution had argued that the case against Connor, which included DNA evidence and CCTV footage, was overwhelming.
But the court held that convictions based on the type of pleas she entered cannot be regarded as safe.
Connor, who appeared via prison video-link, smiled and waved at supporters in the public gallery as the verdict was handed down.
Her barrister successfully applied to have her released on bail until the new trial gets underway.
She is to abide by a curfew, electronic tagging and report to police three times a week.
- UTV's Jordan Moates reports: