Rev Ian Paisley, the former Northern Ireland First Minister had been admitted to hospital. Unconfirmed reports suggest he has suffered a heart attack. Paisley's wife Baroness Paisley confirmed her husband was being treated in hospital.
A family statement said: "She requests that the family's privacy be respected at this difficult time."
The founder of the Democratic Unionist party, and a former MP for Northern Ireland, he was rushed to Ulster Hospital, Dundonald, in Belfast on Sunday.
Ian Paisley attacks Pope's visit to Britain
GOP Senator Scott Brown now the key figure in Irish E3 visa battle
The son of a dissident Baptist minister, Paisley was born in Armagh in 1926. He delivered his first sermon at the age of 16 and founded his own breakaway Free Presbyterian Church in 1951. A well known critic of the Catholic Church he once called the Pope “the Ant-Christ”.
In a historic move he became Northern Ireland’s First Minister in May 2007 after a deal was negotiated to share power with Sinn Fein.
The 85-year-old was the leader of the Democratic Unionist Party for almost 40 years. Last month he stood down from his role as a moderator of the Free Presbyterian Church. He delivered his final sermon at the Martyrs Memorial church in east Belfast just over a week ago.
See below for an Oxford Union speaker profile of Ian Paisley: