"The prison's A Division was closed before because it was deemed to be unsuitable but prisoners have been put back into it in the last few months due the pressures of overcrowding, " a prison officer said.

John Lonergan, governor of Mountjoy, commented: "Last summer two floors of the A Division were reopened. We are now painting single cells and putting in floors to alleviate the use of double cells elsewhere in the prison." Lonergan confirmed that a prefab facility to provide more modern medical facilities at the prison is also being installed at a cost of around 1m.

Eugene Dennehy, deputy general secretary of the Prison Officers' Association, said, "The Prison Officers' Association has always claimed that the closure of Spike Island and the Curragh prison were not thought out and were premature. We believe that the opening of A Division in Mountjoy supports that view."