Sir Bobby Charlton, Manchester United player 1956-1973 and club director, 1984-present day
The record of 19 League titles goes down purely to Alex Ferguson, it would not have been possible without Alex Ferguson, that's for sure. He is the epitome of everything that is good about Manchester United and the ethos of this club. He knows the game inside out. The reason everybody performs to their best is that he is in control, not just of his staff and the first team, but the whole of the club, and as a result it operates in unison. There is no point suggesting anybody else to be manager of Manchester United, there is no one around who can fill his boots. I hope he can carry on for a long time yet. Alex is in control and he is the main reason for the record of League titles.
From the very first game that Alex took over the team, you knew that we had such a talented manager, and it was only a matter of time that he would get it right.
Steve Bruce - Manchester United player and captain, 1987-1996
Sir Alex is the best, there will never be another like him. He has such a huge appetite for achievement.
There is a humility about him that few actually see or are aware of. He has the common touch that he is as appreciative and approachable to the cleaning lady as he is to his captain. He has a way about him that makes people want to play for him. He also has a sensational appetite for the game, and his motivation comes from within. Nobody is going to repeat what he has done, not in my lifetime. Just to be Manchester United manager for 20 odd years is an achievement in itself, let alone all those trophies and honours he has won.
Michael Owen - Manchester United player, 2009-present day
I supposed it's the basic fact that Manchester United have had the best team over the last 20 years. I always think it's important to have stability at a club and Sir Alex has made sure the players had had that. There has been a generation of players who have stuck together, known each others game, and the manager has added players here and there who have complemented these where and when necessary.
Tommy Docherty - Manchester United manager, 1972-1977
He has got to be the greatest manager of them all. He is world class. Messi is the best player in the world at the moment, and Fergie is the best manager in the world at the moment. Cloughie did fantastic with a small club like Forest, Revie and Bill Nicholson were among the very best, but Fergie is the best.
Gordon Strachan - Manchester United player, 1984-1989
It's no fluke that Fergie keeps on winning. Ask anyone who built the best team at St.Mirren, and they will tell you Fergie did, ask anyone who built the best team at Aberdeen, and they will tell you Fergie did, and this legendary period at United is down to the manger, a terrific manager, the best manager, to do it once is good, but three times at three clubs is just ridiculous.
While some clubs have a lull in their trophy cabinet and use that time to rebuild, Fergie tends to reshape his teams when they are winning trophies, and buying the likes of Ashley Young who can pay anywhere in the front four or off the main striker, is one of the typical Fergie signings, a player who can give the team more flair when it needs it.
Peter Beardsley - Manchester United player, 1982-1983, Liverpool player, 1987-1991
Hopefully the situation will now change under Kenny, now that Kenny has returned to Liverpool, and he is the perfect man right now to do something about the 19-18 titles.
But the thought of what happened since 1990 is quite amazing, hard to take in, almost impossible to believe, and really it is down to the fact that Kenny left, and that Sir Alex has been in control of Manchester United's destiny.
Sir Alex is a genius. Sheer genius. What that man has done for Manchester United is scary. What he has achieved at Manchester United will never happen again in the modern game, the number of titles, the number of trophies, the number of teams he has built, it just won't happen again. Everyone tells you about records, that records are there to be broken, but no one will ever win as many Premier League titles as this man. No way will it happen again.
Ray Wilkins - Manchester United player 1979-1984
You have to be a winner to play for United, if you are not a winner with that kind of mentality, then forget it. The club breeds winners, they buy winners. No-one puts his players under more pressure to perform than Sir Alex, as soon as you walk into the place you know you have to be a winner, you have to win, and the players relish that as well if they are the right type; no point being a shrinking violet at Old Trafford. I know from my own experiences there that the players respect the club and hold their traditions dear to them, they are important to them, the players appreciate the fact that they represent Manchester United is a wonderful achievement, that was how I certainly felt. I felt extremely privileged to have played for United.
Garth Crooks - Manchester United player - 1983-1984
Sir Alex is the man who made the difference. He is a like an extra player, more than the manager, and so is an integral part of the team. He contributes with an old school attitude, but he also has a new school approach. The combination makes him so effective. He is a father figure; not prepared to answer questions, threatening to ban reporters, protecting his players from anyone and anything, he will never criticise them in public, won't have them singled out in any way They are his children; there is a father son like relationshp there.'
Wilf McGuinness - Manchester United player 1954-1959, Manchester United manager 1969-1970
We have been blessed with two great managers in Sir Matt Busby and Sir Alex Ferguson, both were brilliant. But to land a record 19 league titles, what can I say about Sir Alex other than I would place him as the highest British manager ever, without doubt. If anyone wants to argue with that they would have to put up a pretty good case, because I cannot see anyone better in the frame.
Paul Parker - Manchester United player - Manchester United player 1989-1995
I get on fine with Sir Alex, always have done, and I love the fellow, because you know precisely where you stand with him. He doesn't bear any grudges. You know when to speak up and when not to, you also know if he tells you what he thinks, he won't hold it against you.
If you go into his office to make your point, nine times out of ten, you will leave wishing you hadn't bothered, as he was invariably proved right. He would produce a video of your performance to prove his point. You walk out of his office, though with a smile on your face, because he was very rarely wrong. If he was wrong, he would hold his hands up, and he would be the first to apologise. But you didn't go around shouting the odds that you had got the better of the Boss because he was wrong and I was right, that was not the way things were done at the club, everything was kept under control with Sir Alex.
Martin Buchan - Manchester United player and captain 1972-1983
Sir Alex has instilled a wonderful work ethic at United, he leads by example, arriving at the training ground every day before anyone else. I know all about his attitude from my playing days, I have the bruises to prove it. I once had the temerity to tell him that he needed to sign a certain type of centre forward. 'Like who?', he asked .'Like Alex Ferguson', I replied. He was a real handful, competitive, determined, energetic, he never let opposing defenders settle on the ball. It's hard enough chasing after forwards, much worse when they come chasing after you and putting you under pressure. It is a wonderful feat to have replaced Liverpool as the top League title holders and I am full of admiration for the way Sir Alex has achieved it.
The one thing about Manchester United is that they never give up, you can never write them off, which is a reflection of the manager's persona. He was like that as a player, and he has instilled that attitude into his club. The number of times they score late in the game illustrates this never say die attitude.
• Harry Harris' new book: 19: The Remarkable Story of United's League Championship Record is available now.