 During interviews, members of the crew mention that the jail scenes  were filmed in Mountjoy prison in Dublin, Ireland and the producer  of the Italian job refers to it also being called Kilmainham.  Mountjoy and Kilmainham are both prisons in Ireland, Mountjoy was  and remains one of the state prisons for convicted criminals;  Kilmainham, which is five miles away, was closed in 1929 and later  converted to a museum.