Peter was President of the High Court until his retirement in 2020. Prior to that he was a Court of Appeal judge. As a High Court judge he set up and managed the Commercial List of that court for the first ten years of its existence. He is a member of the Bars of England and Northern Ireland and a Master of the Bench in Middle Temple London.
He is an adjunct professor of law at Maynooth University. He chaired the Review of the Administration of Civil Justice which reported in October 2020. He is a former chairman of the Investment Committee of the High Court former member of the Courts Service board. He is a member of the Council of the Royal College of Surgeons in Ireland.