It’s four years since Sir Alex Ferguson’s explosive second autobiography hit the shelves.
The legendary Manchester United manager addressed a number of high-profile individuals in the book, including David Beckham, Cristiano Ronaldo, Rafa Benitez and Wayne Rooney.
However, perhaps the biggest criticism in the book was reserved for former United captain Roy Keane, who left Old Trafford under a cloud in November 2005 following a huge bust-up with the fiery Scot.
"The hardest part of Roy's body is his tongue. He has the most savage tongue you can imagine,” Ferguson, who claimed Keane became an increasingly negative influence in the dressing room, wrote.
"He can debilitate the most confident person in the world in seconds. He was an intimidating, ferocious individual."
Ferguson’s honest opinion perhaps, but some United fans were surprised that he decided to write such bitter words about a player who led by example during his 12 seasons playing under him.
Without the exceptional Keane, one of the greatest midfielders of the Premier League era, Ferguson may not have enjoyed as much success throughout the 1990s and early 2000s.
Keane, who would later admit that he cried after his United career was brought to an abrupt end, had the chance to offer an immediate response while working as a pundit on ITV Sport.
Keane's brilliant response to Ferguson
Ahead of kick-off between Arsenal and Borussia Dortmund in the Champions League, ITV presenter Adrian Chiles asked Keane for his reaction to Ferguson’s comments.
And in typical Roy Keane style, the straight-talking Irishman issued a withering response.
"I'm OK, quite relaxed,” he replied before adding: "I remember having conversations about loyalty when I was at the club. I don't think he knows the meaning of the word.
“It doesn’t bother me too much what he has to say about me but to constantly criticise other players that brought him a lot of success, I find very strange. I certainly won't be losing any sleep over it."
After Chiles suggested that Ferguson was out of order for criticising Beckham, Keane said: “I just don’t think he needs to do it. I’m not sure how many books he’s written now but he has to draw the line eventually and say ‘these players have all been top servants to Man United’.
“Can you imagine what he would have said if we’d never helped him win a trophy?
“We brought success to the club, we gave it everything we had when we were there.
“It’s just part of modern life now. People like to do books and criticise their ex-players.”
Ian Wright couldn’t stop laughing.
Asked why he was cracking up, the former Arsenal striker replied: “It’s just the way Roy’s dealing with it!”
Lee Dixon then came out with the line of the night when he said: “I agree with Roy, I don’t understand books at all.”
Chiles jumped on that unfortunate line straight away and you can watch the brilliant video in full below.