The proportion is highest among inmates in the women’s prison at the Mountjoy campus, where 40 per cent of prisoners are receiving methadone or a similar drug

Discussions are ongoing about Portlaoise Prison's future and the potential closure of its IRA wing, now known as E-Wing, as the threat from inmates is considered small.

The periods of release vary from a few hours up to seven nights,

Cleaning services boss Paul Donoghue employs ex-inmates and recovering addicts, giving them an opportunity to reintegrate in society.