Keane was stripped of the United captaincy in October 2005 after a censored MUTV interview saw him slam his teammates following a 4-1 loss to Middlesbrough.
It infuriated Ferguson and he Irishman was hauled in for showdown talks with his manager and chief executive David Gill, which saw Keane leave the club three weeks later.
Keane laid out how the conversation went in his book 'The Second Half' and it's fair to say it wasn't pretty.
"I'd known for a few days they were trying to get rid of me," the 50-year-old begun.
"I said to Ferguson, 'Can I play for somebody else? And he said, 'Yeah, you can. 'Cos we're tearing up your contract.
"I knew there'd be clubs in for me when the news got out. I said, 'Yeah. I think we have come to the end.'
"I just thought, 'F**king p*sstake' and I stood up and went, 'Yeah, I'm off.'"
Keane was given a testimonial by United and was also paid for the remainder of his deal, which was set to expire.
The comments were met with fury from Ferguson who personally addressed them at the time, without actually naming Keane.
"You don't criticise any Manchester United player outside the doors. I have never done and I won't," said Ferguson a week following the incident.
"I am unremitting in that respect. Totally unequivocal. My stance is there and it doesn't change."
Keane did eventually apologise for the comments - but his typical fiery nature came through.
He regrets apologising to this day and questions why he did it further in the book.
"Afterwards I was thinking, 'I'm not sure why I f****** apologised.'
"I just wanted to do the right thing. I was apologising for what had happened - that it had happened.
"But I wasn't apologising for my behaviour or stance. There's a difference - I had nothing to apologise for."
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