Tributes have been flooding in for the legendary Sir Alex Ferguson
Some of football's biggest names have paid tribute to Sir Alex Ferguson, who marks 20 years as manager of Manchester United on 6 November.
Ferguson's achievements during his time with the club have drawn acclaim from past and present players, managers and pundits alike.
MANCHESTER UNITED PLAYERS PAST AND PRESENT
"If you think about another man being there it just wouldn't seem right because he's been there for that long now. He's got the job off to an absolute tee because he's done it for so long and has moulded things around him being there"
Former striker Mark Robins
"He is the best manager of his generation for me. I just know he is a special, special man - I knew he would be a success at United - absolutely no danger"
Celtic boss and ex-Man Utd winger Gordon Strachan
"The thing is, you can't imagine life at United without him. One day it will happen, we are all aware of that, and when it does it will be a great shame because of what he has achieved here. But it won't be soon, because he is still desperate to win trophies"
Midfielder Paul Scholes
"It wouldn't surprise me if he carried on for five to 10 years longer. Why should he leave? He's as determined as ever. It's a continual challenge at this club, that will keep him young"
Captain Gary Neville
"His determination to be the best is constantly on show - even when we're watching The Weakest Link in our hotel he wants to win. He's a one-off and will rightly go down as the greatest ever manager"
Defender John O'Shea
"The manager is making sure the foundations are in place so that players like Rooney and Ronaldo can be the best in the world a few years down the line. That's the way he works and that's why I think he will be around for a few more years yet"
Wing wizard Ryan Giggs
The boss defends his players to the hilt and that's why he gets great respect from the players. They know they can trust him 100%. It is something on which the whole foundations of this club are built"
Defender Rio Ferdinand
"For him to keep going is remarkable. He stands out with his will to win, he knows football, he knows his players and he knows his own club inside-out"
Former United captain Roy Keane
"He is a man with a mission, Manchester United through and through. I'd say his drive was more important to our success than anything else"
Former United midfielder David Beckham in his 2003 autobiography, My Side
"He expected standards to be high and if you didn't reach those standards or you let them slip he would be quick to remind you. He is a fantastic man-manager and great to work under"
Ex-United defender Denis Irwin
"When you think that the average life of a manager is one year and seven days, and somebody has done 20, it is a remarkable achievement. I feel we had some heated times - but time will settle things and there is a respect there now"
Arsenal manager Arsene Wenger
"I once rang him up and was on for 10 minutes about players and he told me about every player, their strengths and their weaknesses. I put the phone down and I said 'I bet he even knows the Dunfermline groundsman' so I rang him back and said 'Hey Alex, I forgot to ask you about the Dunfermline groundsman' and, by God, he did know his name and where he came from!"
Sheffield United's Neil Warnock
"I believe that Sir Alex is number one in England and one of the top two or three in the world. I have found him a nice person, you can talk to him without any problems
Liverpool's Rafael Benitez
"I know the pressure he has had to endure over such a long period, so for him to keep driving himself forward and driving his team forward is a fantastic achievement"
Blackburn's Mark Hughes
"You have to hold your hands up and say Sir Alex is the number one. He has been at the top for 20 years. His desire is unstinting, his passion and will to win fierce"
Wigan's Paul Jewell
"He is a shining light for any young manager who wants to progress. He is probably second to none for what he has done but you can still see that burning ambition in his eyes"
Manchester City's Stuart Pearce
"For what he knew was going to be a massive occasion, to change a player he had previously shown a massive allegiance to, showed that cold, cutting edge that all top managers need"
Reading's Steve Coppell on Ferguson dropping Jim Leighton ahead of the 1990 FA Cup final replay against Coppell's Crystal Palace
"He is the standard bearer for everyone in terms of management. You have to be a very special character to have that amount of success at a club like Manchester United"
Middlesbrough's Gareth Southgate
"Sir Alex is someone I have a great deal of respect for, and someone I would look to emulate one day. If I could match his record it would be fantastic"
Watford's Adrian Boothroyd
"Sir Alex is someone I certainly look up to because he is the one who wins things. He epitomises everything you need in football - stability and continuity, and United believed in him"
Everton's David Moyes
"I'll tell you why he's stayed in the game so long - he just loves it so much. It gets in your blood and you take the job home with you. He's a fantastic character, a top-class manager and a good man"
Portsmouth's Harry Redknapp
OTHER TRIBUTES FROM THE FOOTBALL WORLD
"Sir Alex is one of the most charismatic and successful personalities in the game. I wish him well for the years to come and would like to thank him personally for his tremendous contribution to football"
Fifa president Sepp Blatter
"I'm sure that the House [of Commons] would like to send congratulations to Sir Alex Ferguson for 20 years at Man United as one of the nation's most successful managers and a really nice guy as well"
Sports Minister Richard Caborn
"At the end of United's Treble-winning season in 1999, we were having a cup of tea at the training ground and he was already talking about what was needed for the season after. That's how he's been so successful!"
England manager and ex-United assistant boss Steve McClaren
"He achieves one thing and then, as they say, moves on to the next mountain and the next mountain is higher and that's what he does. He has built four or five successful teams and that proves how great he is"
Ex-England coach Sven-Goran Eriksson
"I'm not surprised he still has the desire, I know Alex very well and he's a fighter and he will always be. I take my hat off to him
Former England manager Sir Bobby Robson
"People did not know how much he used to watch the youth team when the like of the Nevilles, Butt, Scholes and Beckham were in it, he knew every player well. Nobody at Old Trafford thought you could emulate Sir Matt Busby or beat his record. But Sir Alex did and that tells the tale"
Former United youth coach Eric Harrison
"His daily workload is quite extraordinary. It requires as much mental and physical effort you can possibly have. Yet it doesn't seem like he wants to relax"
League Managers' Association chief executive John Barnwell