The wounds collected by Roy Keane when he was driven out of Old Trafford – in that fashion, to one degree or another, which awaits most great players who have exhausted their usefulness – were never going to heal quickly, not in a man notoriously inclined to hold and polish old grievances as though they were a garage full of classic cars.
However, the depth of the bitterness he feels towards Sir Alex Ferguson, the man with whom he once shared so many ambitions, is enough to alarm even those admirers who still believe that he is a football voice that can still be raised with great authority.
It speaks not of someone re-trenching after the disappointments of his early forays into management but something that might just represent entirely the opposite. This, the evidence of his Sunday newspaper attack on his former manager suggests, could be a killing refusal to put behind him those realities of football to which, despite such brilliant service to Manchester United, and Ferguson, he found himself not immune.
There is an additional problem. It is that no-one has ever seemed quite so easy on himself in the matter of handing out blame, for the shocking vengefulness of his tackle on Alf-Inge Haaland, his decision to walk out on the Irish team in the build-up to the 2002 World Cup and the failures of his stewardship of Sunderland and Ipswich Town. He excoriates the weaknesses of others, skips by those of his own.
None of this is to say that some of his criticisms of Ferguson do not carry a breath of validity. However, they become nothing less than risible when he declares: "People say he stood by me in difficult times but he didn't when I was 34, not when I was towards the end and had a few differences with Carlos Queiroz. All of a sudden then, 'Off you go Roy, and here's the statement we've done'."
He then wonders if his relationship with Ferguson wasn't founded on his usefulness to the team. Yes, of course it was. It is the way of big-time football, and it would be interesting to know Keane's view on how their relationship might otherwise have flourished. Neither, let's face it, is the kind of person given to a reflective acknowledgement of arguments and prejudices other than their own. Neither has been known to waste much time on the shaping of a mea culpa.
Keane, after recounting Old Trafford sensitivity to some of his old criticisms, including the arrival of a legal letter, also says: "I've got a son and I always thought I would go back and watch some games with him. Apart from two testimonials, he's not been in the stadium since I left.
"I count my blessings to have played for Manchester United. All of my family are United fans and I don't have any bitterness towards Man United, let's make that clear."
No, just to the man who shaped those years in which Keane was acknowledged by many as the most influential player the Premier League was ever likely to see, the one also who parted company, with no greater ceremony or wistful backward glances, with such as David Beckham, Jaap Stam and Ruud van Nistelrooy.
Keane's last shot is to compare, unfavourably, the personality of Ferguson with that of Brian Clough. It is old angst and maybe a less than shattering blow to the manager who marches on, unreformed and unrepentant and willing, like Keane himself, to turn on his critics at what others might consider the mildest provocation. In this sense, they are similar animals. However, one is in danger of being trapped in his intolerance of everyone's failures but his own. It is not, we can we sure, the latest victim of the apparently unassailable self-belief of Roy Keane.