The Scotsman has been open about his support for the Labour party, but during a Channel 4 interview with Jon Snow, the 71-year-old was probed on whether he was on the Gordon Brown "side of life" rather than Tony Blair.
"I think Tony Blair was a fantastic Prime Minister," said Ferguson. "I used to love him on Question Time, I thought he was absolutely brilliant.
"I've always supported the leader of the party, and I do so at this moment, no matter what kind of criticism we're getting at the moment. Gordon Brown was a fantastic Labour minister. I'm on both sides, I've always supported both of them."
Ferguson's book My Autobiography goes on sale this Thursday.