However, the DUP MLA Trevor Clarke, who sits on the policing board, said the whole process needed looked at.

“I think there’s clear evidence that there was an issue in this case and that’s now been borne out because this person hasn’t come back,” he told BBC Radio Foyle’s North West Today programme.

“All of the things that the courts have involved themselves in this one, I think, has been wrong.

“A chaperone as opposed to a proper prison guard, this is an individual who cannot even handcuff the person while they’re chaperoned, so all of the safeguards that could have been put in place weren’t put in place.”

Sinn Féin MLA Linda Dillon, who also sits on the policing board, said the decision was down to the individual judge, but it is possible that the prison service had not provided them with sufficient information.

“If the prison service did not give all of the information that allowed them to come to the correct decision… then that is something that has gone wrong within the prison service,” she told BBC Radio Ulster’s Evening Extra programme.

Dillon added that questions need to be asked regarding why “the court allowed the prisoner to go with a chaperone who was a lay-person rather than prison officers”.

On Wednesday, the Police Service of Northern Ireland (PSNI) confirmed that Anderson was last seen in the Eastway area of Creggan in Derry.

They also confirmed that they were liaising with An Garda Síochána (Irish police).