An excavation is planned to begin this month in an area thought to contain the remains of the 29 prisoners executed by the State between 1923 and 1954, and potentially the remains of a small number of prisoners executed during British rule of Ireland.

Michael Manning, who raped and murdered a woman in a random attack, was the last person to be executed in the State when he was hanged on 20 April 1954 at the age of 25.

The death penalty was gradually abolished in the following decades. The Criminal Justice Act 1964 allowed the death penalty to be imposed only for the murder of a garda, and it was fully abolished by the Criminal Justice Act 1990.

The Department of Justice has published a full list of the prisoners believed to be buried on the prison grounds, all of whom it intends to reinter “at a suitable location”.

Relatives of the late prisoners who would like to be involved in the project or to seek more information have been invited to contact mountjoyexhumations@justice.ie in confidence.