The former Manchester United manager reveals the full extent of the confrontation which saw him part company with the club captain in 2005
In his new book, My Autobiography, Ferguson provides extensive detail on the rift between player and manager that saw the seven-time Premier League winner leave the club. Ferguson praises his former captain, but believes that he was past his prime when he left Old Trafford for Celtic in the middle of the 2005-06 season.
"Roy Keane was a player of energy, of guts and blood, with a fine instinct for the game and its strategies," Ferguson said. "He was the most influential presence in the dressing room in the time we worked together. But by the time Roy left United in November 2005, our relationship had broken down."
Ferguson believes the reason for the eventual fall-out was the fact that Keane found it hard to come to terms with the fact that he wasn't the same player he had been in his heyday. "I believe - and Carlos Queiroz was at one with me on this - that Roy Keane’s behaviour pattern changed when he realised he was no longer the Roy Keane of old," Ferguson admitted.
"We’re certain of that. Acting on a conviction that some of his strengths had been stolen from him by injury and age, we tried to change his job description, for his benefit as much as ours. I think he could see the truth of what we were saying to him, but to surrender to it was too threatening for his pride.
"That was the long-term context to the confrontation that ended with him leaving the club and joining Celtic. He thought he was Peter Pan. Nobody is."
After a row in pre-season over the club's temporary training facilities in Portugal, Keane gave an interview to MUTV, where he heavily criticised the younger members of the United squad before attacking the senior players. His manager was furious, and summoned Keane to a private meeting. Ferguson admonished his captain "'What you did in that interview was a disgrace, a joke. Criticising your team-mates. And wanting that to go out,'" Ferguson said.
Keane suggested that Ferguson should let the other players see the video. When they did, they were shocked, and arguments started between Keane and the other players. Then the Corkman turned his attentions to his manager. "At that point, players started walking about," Ferguson explained. "Scholes, Van Nistlerooy, Fortune. The hardest part of Roy’s body is his tongue. He has the most savage tongue you can imagine.
"He can debilitate the most confident person in the world in seconds with that tongue. What I noticed about him that day as I was arguing with him was that his eyes started to narrow, almost to wee black beads. It was frightening to watch. And I’m from Glasgow."
Ferguson discussed the player's future with assistant manager Carlos Quieroz, and the duo agreed that there was 'no choice' other than to allow Keane to leave the club. "After the original confrontation, I was finished with him," Ferguson said.
Alex Ferguson's My Autobiography will be released on Friday, October 25.