Today, like every Saturday, Alfie Haaland will be engulfed by regret and resentment. While Mancunian hostilities resume at Old Trafford, and Roy Keane leads United against City, Haaland will be at home in his west Yorkshire village nursing a bad knee and an even worse grudge.

He says he is not bitter but his words are laced with hostility. He does not refer to Keane by his name once. Keane is "he" or "him" or, on one occasion, "that man". And the Norwegian is "very much" taking legal advice about suing Keane and maybe even United, too, because "he set out to hurt me" and "they don't give a damn about anyone but themselves".

The popular misconception was that Haaland, whose career was ended by injury, had decided against putting football through the ordeal of another high-profile court case. But his latest threat should be taken with deadly seriousness. Haaland has been told he has powerful grounds to claim significant damages for the vengeful lunge upon him by Keane in the Manchester derby three seasons ago. It was a moment of bone-crunching violence, perpetrated by an opponent who then confessed in his autobiography it was premeditated.

"I know I have a strong case. I've had about 20 lawyers wanting to take the case, which says it all," says Haaland. "It's certainly not dead, put it that way.

"I probably would have finished with it all by now if it hadn't been for his book and their (United's) attitude. He felt he had to put it in a book (Haaland motions plunging a knife into a body) and I don't have a good thing to say about Man U.

"He has not acted like a normal human being and they are just as bad. It's not envy or anything like that. As far as I'm concerned, they can have all the success they want. But nobody from that club has even admitted it was a bad tackle. They have been twisting the knife all along. You would expect something better - and probably get it - from any other club but that's obviously Man U's attitude towards other clubs and players. They don't give a damn about anyone, you know? It's probably why so many people dislike them."

Haaland has not bought Keane's autobiography but is acutely aware of the passages that set out why the Cork man harboured such a grudge against him. Keane refers to the match at Elland Road in September, 1997 when, playing "bloody awful", he swung a careless leg at Haaland, then of Leeds, and heard his own knee ligaments snap.

Haaland's mistake was to stand over his opponent, apparently shouting at him to stop faking injury. Only Keane knows the silent fury that built up in his mind during his year out of action but it is clear the grudge gradually became an obsession.

Keane recollects that few days passed "when I didn't think about Haaland". He says Bryan Robson told him: "You'll get your chance Roy. Wait." Even now, with the worst expletives removed and with time to reflect on Keane's state of mind, his account of catching up with Haaland reads more like the story of an East End hitman than a celebrated sportsman.

"I'd waited almost 180 minutes for Alfie, three years if you looked at it another way. Now he had the ball on the far touchline. Alfie was taking the piss. I'd waited long enough. I hit him hard. The ball was there (I think)."

Haaland's contract with City was terminated in the summer after three operations and two unsuccessful years of rehabilitation. He was operated on in Ohio by Dr John Bergfeld, the man credited with saving Michael Jordan's career, but his left knee is now in such a state he cannot do any strenuous exercise that requires twisting it. His dedication is admirable, working on it every day in his gym, but there is no guarantee it will save him from growing old in pain. Arthritis, he says, is a near-certainty.

"The doctors can't do miracles," he says, "just the best they can." Keane was given a five-game ban and a record £150,000 fine from the Football Association and the most X-rated extracts were withdrawn when the book's paperback version was published.

Haaland shakes his head as he recalls the vitriol in Keane's words: "It was the worst tackle ever, especially as he obviously set out to do it, as he says in his book. I'll keep what he said to me when I was on the floor to myself but it wasn't nice.

"Most footballers are great, you shake hands at the end and have a beer in the lounge, or a glass of water as it is now. But that man is not normal. He actually went out deliberately to injure another player. And then he felt he had to speak about it in his book. That's what really gets me.

"I was a physical player myself - I could take tackles and stuff like that. But when it's deliberate the person (who does it) obviously has more problems than you. I don't agree with it and hopefully the football world doesn't agree with it.

Pressed on whether he will sue, he says: "I don't know at this moment whether I want to throw all that money at it and go through the procedure of taking someone to court. It's a major thing and, as I say, if he hadn't done that book it would probably have all been forgotten. But because of the book, and because they are who they are, I don't want to leave it."

City, of course, had contemplated legal action of their own, but withdrew the threat. "They were looking at it from their side rather than mine," says Haaland. "They wanted to get some money because the tackle had affected my career and they were thinking about the financial loss to them. They had a lot weaker case than me."

Even though Keane's studs connected with his right knee, is it not the left one that is damaged? "People always say that, but it just makes me laugh. If you ask any doctor or physiotherapist, or anyone who plays the game, they know differently. Where you get the blow you might be bruised and sore for a few days, but it's where your standing leg is on the ground and gets twisted that causes cartilage and ligament injuries. It's as simple as that."

Until now he has been loath to talk, and he is anxious not to come across as downbeat. "I'm not a bitter man," he says, "I'm a positive person. I've had almost 10 years in England and out of those there were seven really good years. Now I'm trying to look to the future. Instead of looking back and being angry I want to look ahead."

Besides, there is plenty to occupy him. Haaland and his wife Marita have settled in England with their three children, Astor, Gabrielle and Erling, so "everything right now is shepherds, angels and Santas".

Haaland has also joined the board of Bryne, the club where he began his career.

He will look back at more than 200 Premiership appearances and some "great memories" - helping Leeds to a Champions League semi-final, a UEFA Cup quarter-final with Nottingham Forest and 32 caps for Norway.

He smiles to recall his days at Forest: "Apart from Stan Collymore, it was a good club. He used to miss so many training sessions Frank Clark said to him one day: 'I can't believe you still have any family members alive, you go to so many funerals'.

" I remember teasing him one day and, bosch, he punched me. I was on the floor."

Haaland is laughing now. Compared with Roy Maurice Keane, falling out with Stanley Victor Collymore was child's play.