Ferguson criticised Keane in his autobiography last year and Keane has hit back at the former United manager with a host of barbs and criticisms in his own book.
The Second Half, Keane's updated autobiography, was due to be released on Thursday, but a Tesco store in Burnage made a huge blunder by putting the books on sale 72 hours early and the contents were published by national newspaper websites soon after.
Keane was the main recipient of the hair dryer treatment in Ferguson's book and it appears the Irishman has returned the favour by hitting out at his former boss in The Second Half.
Keane says Ferguson was ill-advised to pursue a legal case against John Magnier and JP McManus over the stud fees from the Rock of Gibraltar racehorse.
And the former United captain effectively withdrew an apology he gave to Ferguson after the MUTV interview in which Keane was alleged to have criticised several of his team-mates.
''Now I kind of wish I hadn't (apologised)
Afterwards I was thinking, 'I'm not sure why I f****** apologised'
I just wanted to do the right thing,'' Keane writes, according to the newspaper websites.
Ferguson claimed Keane challenged his authority with the criticism of several members of the United squad, including Rio Ferdinand, Darren Fletcher and Alan Smith.
But Keane, who claims in the book that someone at United leaked details about the tape, says his criticisms were not harsh.
"The idea that I was in the studio ranting and raving, no..
I was told the interview was being pulled
They couldn't believe what I had said
I didn't think it was too bad
I thought everyone was overreacting."
Keane does not try to play down the severity of a row with Ferguson, and his assistant Carlos Queiroz, who apparently accused the former United skipper of disloyalty.
Keane writes about his exchange with the Portuguese: ''I said, 'Don't you f****** talk to me about loyalty, Carlos
You left this club after 12 months a few years ago for the Real Madrid job
Don't you dare question my loyalty'.''
The Irishman then directed his ire towards Ferguson, who had stepped in to stop the row between his assistant and captain.
''You as well gaffer
We need f****** more from you,'' Keane claims he said to the United manager
''We need a bit more, gaffer
We're slipping behind other teams.''
Keane, who moved to Celtic to play out the final five months of his career, claims his departure from United cost him a lot of money because he was due to receive a £1million bonus if he had played in 50 per cent of the first-team games in that 2005-06 season.
When Keane was called into Ferguson's office in November 2005, he says he knew the manager was going to inform him he wanted him out of the club.
Keane writes: ''I said to Ferguson, 'Can I play for somebody else?' And he said, 'Yeah you can, cos we're tearing up your contract'
So I thought, 'All right - I'll get fixed up'
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******' p****' - and I stood up and went 'Yeah
I'm off'.''
In the book, Keane also writes about a drunken fight with Peter Schmeichel, hits out at Rio Ferdinand for missing a drugs test, and claims he does not regret making the tackle that effectively ended Alf-Inge Haaland's career - although the Irishman says he never intended to hurt the former Manchester City midfielder.
Source : PA
Source: PA