A prisoner exchange treaty with Iran has been upheld by Belgium’s highest court, opening the door to a possible inmate swap.
The ruling means it might be possible for jailed Belgian aid worker Olivier Vandecasteele to be freed in exchange for Iranian diplomat Assadollah Assadi, imprisoned for his role in a bomb plot.
Belgian lawmakers cleared the treaty in July but it has been held up by legal challenges from an exiled Iranian opposition group.
“The court rejects the action for annulment,” Belgium's constitutional court said on Friday.
Judges specified that the victims of any detainee being proposed for transfer must have the right to contest the specific case in court.
“Thus, when the government takes a decision to transfer, it must inform the victims of the relevant convicted person in such a way that they can effectively seek a review of the legality [of the transfer],” it said.
The decision was a blow to the Iranian opposition group, the National Council of Resistance of Iran, which brought the case.
It had said that the law would reward Iran for taking hostages by allowing it to swap them for jailed agents.
After Friday's judgment, campaigners for Mr Vandecasteele's release tweeted there was “still a [long] way to see Olivier free but tonight there might finally be a light at the end of the tunnel”.
Mr Vandecasteele, arrested while on a visit to Iran in February 2022, was sentenced in January to 40 years in prison and 74 lashes on charges including spying that Brussels has denounced as fake.
His distraught family has appealed to the government to do its utmost to get him freed.
Olivier van Steirtegem, a friend of Mr Vandecasteele, said in January that he had lost 25 kilograms and suffered from ear, stomach and dental infections that have not received proper medical attention.
Mr van Steirtegem said Mr Vandecasteele has been in solitary confinement since his arrest and lights are always on in his six-square-metre basement cell.
Iran, meanwhile, has called for the release of Assadi, sentenced to 20 years in prison in Belgium in 2021 over a foiled 2018 bomb plot. His was the first trial of an Iranian official for suspected terrorism in Europe since Iran's 1979 revolution.
He was found guilty of supplying explosives for a planned bomb attack at an event outside Paris held by NCRI.
Belgian police thwarted the attack when they intercepted a car carrying the bomb, acting on information gathered by several European intelligence services.
Assadi had brought the explosives on a plane from Iran and handed over a device to a husband-and-wife bombing team after a meeting at a Pizza Hut in Luxembourg City.
He kept in contact with them until they were arrested as they drove to the rally attended by an estimated 25,000 people in Villepinte, on the outskirts of Paris.
Attached to Iran's embassy in Austria, Assadi was arrested in Germany, where his claim for diplomatic immunity was denied.
The treaty, signed by the Belgian Justice Ministry and the Iranian ambassador to Belgium, says that “the best way” to boost co-operation with Iran in matters of justice was to allow convicts to complete their prison sentences in their home countries.
It also allows that each jurisdiction might pardon the returned convicts or commute their sentences.