A prisoner who claims he has been isolated in his cell in Wheatfield Prison for up to 23 hours a day for more than a year is seeking a High Court declaration that he is being subjected to cruel, inhuman and degrading punishment.
However, the prison's governor has denied the claims by Jason O'Connor, and has argued he is being segregated for his own safety because there is a credible threat to his life.
O'Connor is serving a three-year sentence since July 2005 for burglary, criminal damage and handling stolen property.
Yesterday, Michael O'Higgins SC, for O'Connor, said his client was entitled to be detained in a different manner to segregation. While gardaí were satisfied the threat to the life of his client was a real one, his segregation and isolation were having serious adverse effects.
In an affidavit, O'Connor said he has been subjected to a special segregation regime in the prison since March 2006.
He was told the reason for this was because of a suggestion that others may have been harbouring an intention to harm him. His detention under such a regime was for his own good.
O'Connor said the most difficult aspect of the regime was his social isolation and the lack of any activity with which to divert himself.
He said he was effectively locked within his cell for 23 hours a day.
The only time he was outside the cell was an hour or occasionally 90 minutes for exercise.
He said while the general population of the prison was permitted to attend school, the gym, workshops and computer classes, no such facilities were given to those in the special segregation regime.
The governor claims O'Connor is not entitled to the relief sought, and contends it was O'Connor who had expressed fears to gardaí that his life may be at risk.
The governor also denies that the regime under which O'Connor is being detained amounts to a punishment regime, and says the sole purpose of the regime is to protect O'Connor.
He says there is a real and credible threat to O'Connor's life, and the segregated area in the prison is considered the safest area for him.
Mary Ellen Ring SC, for the governor, said the prison authorities had acted properly. O'Connor was not isolated or suffering from any form of "sensory deprivation".
She said if the authorities saw that the threat to O'Connor's life no longer applied there would be no impediment to him returning to the rest of the prison population.
Mr Justice Roderick Murphy said he would rule on the matter today.