Supreme Court judge Mr Justice Adrian Hardiman has passed away.
Mr Hardiman was involved in a number of high-profile cases and was well known for his broadcasts and writings on legal and political matters.
Chief Justice Susan Denham has paid tribute to him saying she received the news with great sadness and shock.
She said Justice Hardiman was "a man who had made great and courageous efforts on behalf of those who sought justice.
"He neither favoured nor feared any interest - and went about his work with great integrity, grit and dedication."
He is survived by his wife retired Judge and author of the Murphy report Yvonne Murphy and three Children.