Top-secret reports into alleged shoot-to-kill cases are to form part of a bid by one of the Colombia Three to have his weapons conviction overturned, senior judges have heard.

Even though Martin McCauley faces extradition to South America if he returns to Northern Ireland, his challenge to being found guilty of having three rifles 30 years ago is continuing at the Court of Appeal in Belfast.

The 51-year-old, from Lurgan, Co Armagh, was arrested along with Niall Connolly and James Monaghan in Colombia in 2001 and accused of IRA training of rebel Farc guerrilla forces.

At the time the three men’s detention threatened to destabilise the Northern Ireland peace process. They were initially cleared of the charge, only to be convicted on appeal and sentenced to 17 years in jail.

But the three men avoided imprisonment by fleeing Colombia in 2004, turning up in the Irish Republic a year later.

McCauley is now appealing a conviction for having weapons in suspicious circumstances in 1982 for which he received a two-year suspended jail sentence.

He was charged after being shot and wounded by an RUC team at a farm shed near Lurgan where the antique-style guns were discovered.

His 17-year-old friend Michael Tighe was killed in the operation.

That death was one of six cases John Stalker, the former assistant chief constable of Greater Manchester Police, and Sir Colin Sampson of West Yorkshire Police, investigated to try to establish whether police intended to kill.

McCauley’s lawyers argue the conviction should be quashed because events at the farm shed were recorded by police but never disclosed to the defence at trial.

The case was referred back to the Court of Appeal by the Criminal Case Review Commission, set up to examine miscarriages of justice.

The body has supplied a confidential annex to back its belief that the conviction is unsafe.

Central to the challenge are the contents of the Stalker and Sampson reports, which have never been made public.

Their findings have been made available to the families in the shoot-to-kill cases and their lawyers, but only for the purposes of holding inquests and after they gave signed undertakings not to disclose details.

McCauley has also seen their contents due to his status as a key witness in the Tighe case.

The Court of Appeal heard on Friday that formal permission to use the reports in his challenge to the weapons conviction will now be sought from senior coroner John Leckey.

Lord Chief Justice Sir Declan Morgan agreed to list the case for a further update in June.

Outside the court McCauley’s solicitor Fearghal Shiels, of Madden and Finucane, said: “My client has had access to the Stalker/Sampson reports which are central to his appeal.

“He has this in his capacity as a main witness to the inquest into the death of Michael Tighe.”