He had been in the care of the Little Sisters of the Poor in Newcastle, but was hospitalised after a fall in February.
The Cardinal resigned as Archbishop of the Archdiocese five years ago after admitting sexual misconduct.
Archbishop Leo Cushley, St Andrews & Edinburgh, said: “In life, Cardinal O’Brien may have divided opinion – in death, however, I think all can be united in praying for the repose of his soul, for comfort for his grieving family and that support and solace be given to those whom he offended, hurt and let down. May he rest in peace.”
He received the Sacrament of the Sick on Saturday after Archbishop Cushley, visited him in hospital.
Cardinal Keith Michael Patrick O’Brien, was born on 17 March 1938 in Ballycastle, County Antrim, Northern Ireland.
He was ordained a priest on 3 April 1965. He obtained a bachelor of science degree in chemistry and mathematics from the University of Edinburgh and a diploma in education.
Cardinal O’Brien served as assistant parish priest and as chaplain of St Columba Secondary School in Cowdenbeath, where he taught math. He was spiritual director of St Andrew's College in Drygrange and rector of St Mary’s College, Blairs. On 5 August 1985 he was ordained Archbishop of Saint Andrews and Edinburgh. In 1991, Archbishop O’Brien was awarded the Equestrian Order of the Holy Sepulchre of Jerusalem: Knight Commander with star. From 1996-1999 he served as Apostolic Administrator of the Diocese of Argyll and The Isles.
From March 2002 until 2012, Cardinal O’Brien was President of the Bishops’ Conference of Scotland. Archbishop emeritus of Saint Andrews and Edinburgh, 18 February 2013. Cardinal Keith O’Brian did not participate in the conclave of March 2013. In May 2013, in agreement with Pope Francis, he left Scotland for a period of spiritual renewal, prayer and penance.
In March 2015, the Holy Father Francis accepted the resignation of the rights and privileges of a Cardinal, expressed in canons 349, 353 and 356 of the Code of Canon Law, presented by Cardinal O’Brien, after a long period of prayer. He participated in the conclave of April 2005, which elected Pope Benedict XVI.