A Newry man jailed after being caught in a covert MI5 operation targeting the Continuity IRA has lost a High Court battle over his continued detention.
Seamus Morgan, 65, is serving a prison sentence for belonging to a proscribed organisation.
Originally due to be released on licence in June this year, he issued proceedings after newly introduced terror legislation pushed that date back by at least six months.
But senior judges today dismissed his application for a writ which would have seen him let out of jail.
Mrs Justice Keegan held that Morgan is being lawfully detained under laws introduced by the UK Government which extend the custodial period from half to two thirds.
"It is clear and unambiguous that the legislative intention was to change the regime for serving terrorist offenders," she said.
"This piece of legislation was designed to have retrospective effect. It was designed to extend to Northern Ireland."
Morgan, with an address at Barcroft Park, was among seven men jailed in connection with an undercover operation centred on meetings at a house in Newry back in 2014.
In November 2020 he received a three-year sentence after pleading guilty to the charge against him.
Morgan was told he would serve 18 months in custody and 18 months on licence, with his release originally set at June 24.
However, new laws brought in following terror attacks at Fishmongers Hall and Streatham in London mean his revised earliest release date is now December 25.
Under the Counter Terrorism and Sentencing Act 2021 offenders in Northern Ireland must now serve two thirds of their term behind bars.
Their cases also have to be referred to Parole Commissioners before any release.
Lawyers for Morgan argued that he should not be subject to the legislative amendments, and that his human rights were violated.
They claimed that he has now served the custodial term imposed on him.
Rejecting those submissions, Mrs Justice Keegan, sitting with Lord Justice Treacy, held that the new clause extending the period in prison applied to him.
The judge added that it was beyond the court's powers to rewrite primary legislation.
"In simple terms, the making of law is reserved to Parliament, the interpretation of law is for the courts,'' she said.
Mrs Justice Keegan confirmed: "By virtue of this provision of law he is lawfully detained.
"It is not possible for the court to read the legislation in any other way which would allow the court to issue a writ of habeas corpus."