Counsel for the DPP has argued that the conviction of Colm Murphy on a charge arising from the 1998 Omagh bombing is safe and satisfactory despite a "difficulty" with the evidence of two gardaí who were found to have perjured themselves.
Mr Peter Charleton SC said admissions by Murphy to gardaí were "powerfully" supported and corroborated by telephone evidence.
He was making submissions on behalf of the DPP on the third and final day of Murphy's appeal against his conviction by the non-jury Special Criminal Court on a charge of conspiracy to cause an explosion. He was jailed for 14 years.
Murphy remains the only person to be convicted on a charge arising from the Omagh bombing of 1998 in which 29 people died.
At the close of the appeal, Mr Justice Kearns, with Mr Justice Clarke and Mr Justice McMenamin, said the court would reserve judgment.
Yesterday, Mr Charleton said the Special Criminal Court had been satisfied there had been no interlinking between two gardaí who were found to have perjured themselves at the trial and four other investigating gardaí.
There was no legal basis for claiming that established wrongdoing by one member of an investigation team invalidated an entire investigation, he said.
Murphy had from various admissions accepted membership of a continuity of organisations, counsel added.
It was likely, he said, that such organisations would have committed atrocities at Banbridge and Omagh. As a matter of fact, Murphy was chosen to assist a "mission" at Banbridge and when it came to the "mission" at Omagh he could have had no doubt by reason of the previous use of his cell phone that those "republican elements" seeking his assistance were doing so because of his "republican sympathies".
There was "no contest" that Murphy did not have his phone over the three days of the Omagh bombing, counsel said.
The Special Criminal Court was obliged to analyse such evidence to determine whether that element of a logical picture presented by Murphy as the reason for his involvement in Banbridge and Omagh fitted with the facts adduced in evidence before the court.
Mr Charleton said the Court of Criminal Appeal had to look at the reality of the situation.
There was evidence that a bomb was assembled in the Dundalk area and moved through Aughnacloy to Omagh.
Where a person assembled the components of an explosive device, then each item, whether it be container, sealant, explosive, detonator, wire or radio device to effect detonation, constituted in itself an explosive substance.
Counsel said the Special Criminal Court had found that the arresting garda was aware at the time of Murphy's arrest that he had a criminal record for terrorist crime and believed Murphy was associated with known terrorists.
The same garda believed that Murphy's phone was used in connection with the transport of the bomb to Omagh.
The garda was aware of the movements of Murphy's phone and of the phone of another person and calls on the afternoon of the bombing which appeared to link the two men with the bomb's journey to and from Omagh at the times relevant to the bomb's detonation.
There was a "seamless continuity of facts" between the conspiracy that planned this event, the persons who assembled the bomb, those who travelled to put it in place, the people who detonated it and those who lent their aid to proffering "clean clothes" or "apparently unconnected" mobile phones for the operation.