Despite being the most successful manager in the English game and revolutionising United, there are aspects that sully his reputation.
As well as a poor return in Europe, there have been transfer failures, unseemly legal squabbles over the horse Rock of Gibraltar and he over-stepped the mark with his 'hairdryer' treatment when kicking a boot at David Beckham. He was soon sold for crossing the boss - as were Paul Ince, Jaap Stam, Roy Keane and Ruud van Nistelrooy.
But that is all part of the man's fabled character that makes him feared and feted in equal measure.
He has said: "You mellow a bit but the inner desire is just the same."
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