[4] After the Second World War, he took over a farm at Benshie, Angus, and subsequently set up a cattle ranch at Braeroy, Inverness-shire, near Spean Bridge.
He lost his seat in 1966, when he was defeated by the Labour candidate Robert Maclennan, who was to become a party colleague of Mackie in the late 1980s after he joined the Liberal Democrats via the SDP.
Having been appointed a Commander of the Order of the British Empire (CBE) in 1971,[6] he was given a life peerage, as Baron Mackie of Benshie, of Kirriemuir in the County of Angus on 10 May 1974.
[7] In the House of Lords, he served as Agriculture and Scottish Affairs spokesman for the Liberals and their successor parties between 1975 and 2000.
[2] Until his death, Mackie was the oldest living person to have served as a Liberal Member of Parliament in the United Kingdom.