Good morning all! It's safe to say the biggest football news story of the year has broken today. Manchester United manager Sir Alex Ferguson has announced that he will retire at the end of the season.

Rumours rumbled overnight claiming that the Scotsman was considering whether to step down, and the club have since confirmed that the rumours are indeed true! A statement from the club this morning said: "The most successful manager in English football history will bow out after the West Bromwich Albion game on 19 May and join the football club board."

As for Ferguson, the successful manager has claimed that it is the "right time" to go after guiding the club to their 20th league title a matter of weeks ago. Ferguson said: "The decision to retire is one that I have thought a great deal about and one that I have not taken lightly. It is the right time.

"It was important to me to leave an organisation in the strongest possible shape and I believe I have done so.

"The quality of this league winning squad, and the balance of ages within it, bodes well for continued success at the highest level whilst the structure of the youth set-up will ensure that the long-term future of the club remains a bright one."

David Gill and the Glazer family have also had their say on Ferguson's departure. You can read the full statement here.

So, have you had time to breathe yet? Ferguson may have retired as manager but he isn't abandoning the club altogether. The club have confirmed that he will move upstairs as a director and ambassador.

Before we get some reaction, let's have a look at what Ferguson leaves behind. The Scotsman is the most successful manager in British football history and here's why:

Premier League: 1993, 1994, 1996, 1997, 1999, 2000, 2001, 2003, 2007, 2008, 2009, 2011, 2013
FA Cup: 1990, 1994, 1996, 1999, 2004
League Cup: 1992, 2006, 2009, 2010
Uefa Champions League: 1999, 2008
Fifa Club World Cup: 2008
Uefa Super Cup: 1992
Uefa Cup Winners Cup: 1991
Inter-Continental Cup: 1999
FA Charity/Community Shield: 1990 (shared), 1993, 1994, 1996, 1997, 2003, 2007, 2008, 2010, 2011

There were no indications throughout the season that Ferguson was going to step down, and he even stated in the match day programme against Chelsea that he had no plans to step down.

He wrote: "I don’t have any plans at the moment to walk away from what I believe will be something special and worth being around to see.

"It’s always difficult in football to be absolutely sure of the future because the game has a habit of tripping you up, but I don’t live in a fantasy world and believe we have every reason to feel confident about the future of Manchester United. My view stems not from the euphoria of winning back the title we lost last season, but on the way we did it and the make-up of our playing personnel."

Despite his claims, there have been suggestions that his health has become an issue. The 71-year-old is due to undergo hip surgery this summer, which could have put him on the sidelines for a number of months. Some have also suggested that David Gill's impending departure at the end of the season has played a part in Ferguson's decision to go.

The tributes are coming thick and fast! One being from United rival Vincent Kompany, who lifted the Premier League trophy for Manchester City last season.

The defender tweeted: "Sir Alex, one of the best managers of all time. After 26 years of success in the game, we all owe him a tribute."

Current Blackpool manager and former United midfielder Paul Ince has admitted that he never expected Ferguson to retire at the end of the season.

Ince told Sky Sports News: "I'm totally shocked. What's he's done in unbelievable. You'll never see anyone of his kind again.

"Two weeks ago he was talking about staying on for another two years, so it's a massive, massive shock. The way he treated me was like a son."

While Ferguson's tenure at Old Trafford will be remembered, Ian Stirling of the Independent Man United Supporters Trust believes that what happens next could be a shock for some of the club's fans.

"What you have is a large proportion of the crowd who only know Sir Alex Ferguson as the manager," Stirling told BBC News.

"They don't remember the past managers. It is going to be an interesting time for these supporters. Older Reds like myself remember the transitional periods and it can be dangerous times."

Speaking of what happens next, my colleague Liam Apicella has listed the early top five contenders for the vacancy at United. David Moyes, Jose Mourinho and Jurgen Klopp are among the contenders. Have a look here.

As mentioned, Everton boss Moyes has been linked with becoming Ferguson's successor over the last few years and following today's announcement, rumours have intensified. However, earlier today Everton dismissed suggestions that the Scotsman plans to make an imminent decision on his future.

Greg O'Keeffe of the Liverpool Echo tweeted: "EFC say they're unaware of anything imminent in terms of a decision from David Moyes on his future today. #manutd #alexferguson"

UPDATE! It has been claimed by Sky News journalist Mark Kleinman that United could announce a managerial replacement within the next few days.

He wrote on Twitter: "Manchester United source tells me Sir Alex Ferguson's successor will be announced within days but has to resign from current role first...

"My #MUFC source also tells me club's board has been in talks with Fergie's successor for some time. Rules out neither Moyes nor Mourinho."

Michael Owen, who played under Ferguson for three years, has had his say on the Scotsman's decision to step down.

The striker wrote on Twitter: "It's just not sinking in! Manchester United with no Sir Alex just doesn't feel right. What a man and great that it has ended on his terms. What a privilege to have played under arguably the best manager the world has ever seen.

"His record will surely never be eclipsed. Simply astonishing to read through his managerial record of achievements."

Owen has also been discussing who could take the hotseat at Old Trafford. David Moyes and Jose Mourinho are the frontrunners as far as the bookmakers are concerned.

Owen tweeted: "What an act to follow. I guess only Mourinho would have the confidence to strut through the door. If it were me, I'd go for Moyes."

FIFA president Sepp Blatter has also reacted to today's huge news.

He wrote on Twitter: "Just heard Sir Alex Ferguson is retiring at end of season. His achievements in the game place him without doubt as one of the 'greats'. Was honour to present Sir Alex with award at 2011 Ballon D'Or. Will his longevity at the top ever be repeated?"

Professional Footballers' Association chief executive Gordon Taylor believes that football as a whole will miss the presence of Sir Alex.

"The game of football will be a lot poorer place without him. He has been quite simply the best. He followed in Sir Matt Busby's footsteps and even surpassed him. He will be also be the toughest act to follow."

Someone who seems to be distraught at the news is former United goalkeeper Peter Schmeichel.

He's said: "Disappointed, shocked, sad. Didn't think THAT day would be today."

UPDATE! According to Sky Sports News, one of the bookies' favourites David Moyes has moved into pole position to take the reins at Old Trafford this season. Well, if this is in fact true, it'll be a huge task for the Scotsman, who has spent 11 years at the Merseyside club, establishing them as a top-six side, but he has failed to clinch silverware while at the club.

You could argue that perhaps Moyes has been waiting for the call as he has maintained throughout the course of the season that he won't make a decision regarding his future until the summer. However, reports have claimed that the Scotsman has been locked in discussions regarding Everton's transfer plans for the window, so who knows! At this moment, it's all speculation, but it seems as though Moyes is the frontrunner.

Prime Minister David Cameron has also been weighing in on the huge football news of the day.

He wrote on Twitter: "Sir Alex Ferguson’s achievement at #MUFC has been exceptional. Hopefully his retirement will make life a little easier for my team #AVFC"

UPDATE! Further suggestions that Moyes is the man leading the pack to replace Ferguson come from Sky Sports News, who claim that sources within the club are "not looking for a quick fix", and that Moyes "respects the history and development of the club and he is cut from the same cloth as Ferguson." Moyes has proved his loyalty by remaining at Everton for over a decade, while Mourinho, for example, tends to spend around three seasons at a club before moving on. Once again, it is all speculation at this point.

United's Premier League rivals Chelsea, who are rumoured to be reappointing Jose Mourinho in the summer, have paid tribute to Ferguson via their official Twitter page.

"All at Chelsea would like to wish Sir Alex Ferguson the very best in his retirement. He has been a fantastic adversary over 26 years."

Let's not forget that Mourinho is still a contender for the United vacancy. While it has been widely suggested that the Portuguese coach will return to Chelsea, reports last night have suggested that negotiations between Mourinho and owner Roman Abramovich have hit a snag. Could Ferguson's decision be down to acting quickly in order to snatch Mourinho?

Queens Park Rangers player Shaun Wright-Phillips has had his say on Twitter: Shaun Wright-Phillips writes on Twitter: "#Salute to Sir Alex Ferguson definitely the greatest premier league manager the countries ever seen. Correction greatest football mgr ever."

West Ham United and Arsenal have also paid their own tributes to the successful manager.

West Ham: "Everyone at #WHUFC would like to wish Sir Alex Ferguson a very happy retirement following 26 successful years as Manchester United manager."

Arsenal: "Everyone at Arsenal wishes Sir Alex Ferguson health and happiness following the announcement of his retirement as Manchester United manager."

We already know of Sir Alex's prolific record of silverware, but let's take a look at his all-time match record at United from November 6, 1986.

Played: 1604
Won: 965
Drawn: 360
Lost: 279

Former Manchester United midfielder Lou Macari has expressed his shock at Ferguson's retirement.

He told MUTV: "It really has caught me by surprise. My phone kept ringing all morning and I thought it must be something serious. When the news comes through, it's about the manager, which is serious if you're a Manchester United supporter, everybody will be a little bit concerned. Can the next guy coming through the door do what Sir Alex has done? That's going to be tough."

The FA have paid tribute to Ferguson's "outstanding" contribution to the English game via chairman David Bernstein.

FA Chairman David Bernstein has reflected on Sir Alex's 'extraordinary' achievements.

"Sir Alex Ferguson’s achievements are truly remarkable – he is genuinely one of the greatest managers of all time and certainly of the modern era.

"His contribution to English football has been outstanding in every regard and, in The FA’s 150th year, it is something that should be celebrated. On behalf of The FA I’d like to wish him a happy and healthy retirement."

United coach Rene Meulensteen has been speaking to Sky Sports News saying that Ferguson informed the coaching staff of his decision this morning.

He said: "[Ferguson] called us into his office and said what decision he took. Its always been on the cards, I think the manager kept his cards close to his chest. I think he felt the time was right. He's been absolutely fantastic for this club and I hope the fans will give whoever comes in the same support that Ferguson got."

Meulensteen was also asked how Ferguson was feeling when he saw him at the Carrington training ground this morning. He responded: "I think a combination of relief in some ways."

Celtic manager Neil Lennon believes that no other Man United manager will be able to reach the same feats as Ferguson. He tweeted: "The game just won't be the same without Sir Alex… what a contribution he has made to the game… doubt anyone will ever replicate it."

BBC Sport journalist Phil McNulty believes that United have had Ferguson's replacement in mind for some time.

"It takes a leap of imagination to believe Manchester United do not already have Sir Alex Ferguson's chosen successor in place. The choice is an interesting one. Do they go for the charisma, successes - but essentially quick hits - of Jose Mourinho or the stability they know Everton's David Moyes would give them? In trophy terms there is only one choice but United will want to consider the wider context."

Former United striker Louis Saha has questioned Ferguson's health following the manager's retirement. The forward wrote on Twitter: "Wow S A Ferguson leaving. Hope is [sic] health ok. He is the most powerful man i ever met in my life after my dad. Huge respect for Football God."

Premier League chief executive Richard Scudamore has also paid tribute to Ferguson.

"The Premier League has had the privilege to witness many great players, managers and teams," BBC Sport quotes Scudamore as saying. "No one has made as great a contribution to the Premier League than Sir Alex Ferguson.

"His drive, ambition, skill, passion and vision have not only shaped Manchester United, but in many ways the game of football as we now know it. Sir Alex and his teams during the Premier League era have set the pace others have had to follow; 13 titles out of 21 seasons is a phenomenal achievement."

Just to show how long Ferguson has been at the helm of Old Trafford, the Daily Mail has dug out the stat that 14 players of the current first team weren't even born when Ferguson became United boss.

They are: David De Gea, Rafael, Phil Jones, Jonny Evans, Anderson, Chris Smalling, Javier Hernandez, Nani, Danny Welbeck, Tom Cleverley, Nick Powell, Shinji Kagawa, Alex Buttner, Ben Amos.

Former Red Devil Ruud van Nistelrooy has written on Twitter:"2001-2006, 219 games, 150 goals under the most successful manager in football history. It was a unique privilege." #SAF

As planned, the Man United team bus has left for the Chester Races, but according to Sky Sports News, Ferguson is not on board. I presume that's to avoid the media attention that he would not doubt receive.

While Ferguson may not be in attendance, his horse 'Butterfly McQueen' is running in the 3.50pm Boodles Diamond Maiden Stakes at 11-1.

My Sports Mole colleague Liam Apicella has been busy writing up a profile of Ferguson's glittering career at the North-West club. Have a read of it here.

While Ferguson's retirement confirmation has dominated news coming out of United, the club also announced plans for their open-top bus parade today.

On Monday, Ferguson will address the fans alongside his players at a send-off event at Old Trafford at 6pm, which will then be followed by the bus parade at 6.30pm. The parade will leave Old Trafford and drive through the streets of Manchester before concluding the route at Albert Square.

Following Ferguson's retirement, let's revert back to his post-match interview with Sky Sports after United clinched their 20th league title courtesy of a 3-0 victory over Aston Villa. Watch it below:

Cristiano Ronaldo, who left United after six years at the club for Real Madrid in a record £80m deal, has expressed his gratitude towards Ferguson on Twitter with a simple message, "Thanks for everything, Boss," followed by a photo of the pair on the day that Ronaldo signed for United when he was a teenager.

Of course, there have been rumours that Ronaldo could return to the Premier League outfit this summer, but following today's news, a possible transfer could be up in the air. A similar story could be told for Wayne Rooney, who today, has been linked with a £30m move to Bayern Munich.

Former world number one golfer Rory McIlroy, who is a Manchester United fan, tweeted: "An end of an era. Sir Alex Ferguson, the greatest of all time. United will have a tough time trying to replace him."

UPDATE! As we all know, rumours have been rife that Everton boss David Moyes is in pole position to replace Sir Alex. It appears that those rumours are gathering pace as Everton correspondent for the Liverpool Echo Greg O'Keeffe has suggested that it is just a matter of time before Moyes moves into the hotseat.

O'Keeffe wrote on Twitter: "Increasingly hearing that David Moyes WILL leave #EFC to succeed Alex Ferguson at #MUFC in the summer."

UEFA president Michel Platini has paid tribute to the legendary manager's "unique eye for talent". BBC Sport quotes Platini as saying: Uefa president Michel Platini: "Sir Alex has made a massive contribution to football, not only in Scotland and in England, but across Europe and beyond.

"His dedication, his attention to detail and his unique eye for talent, as both the manager of Manchester United and Aberdeen, has brought rich rewards over a 30-year period. His CV is almost unique in a results-based profession that normally focuses on short-term solutions rather than long-term vision."

As we've mentioned, Moyes appears to be the frontrunner, and ex-United captain and current Hull City boss Steve Bruce believes that the Scotsman is a likely appointment.

"It would not surprise me," Bruce told Sky Sports News. "He's a very talented manager who has been at Everton for more than 10 years. He's not had huge finances but he has still managed to put an Everton team together that will comfortably finish in the top 10. He has been in the job a long time and he has all the credentials to be a top manager for Manchester United."

United chief executive David Gill made a statement on the club's official website at the time of Ferguson's retirement announcement, but he has been speaking further on MUTV.

Gill, who will step down from his role at the end of the season, has claimed that the club have been "preparing" for the inevitable.

"It is a new era and I look forward to watching a successful Manchester United team on the pitch," Gill told the club's official channel. "It is a momentous day for the club, the fans and the whole football world.

"We knew this day would come and we have been preparing for this. The board will take council from Sir Alex and Sir Bobby [Charlton] on new appointment. Working with Sir Alex has been the highlight of my career."

Marseille midfielder Joey Barton has had his say on Twitter, claiming that taking on the United job would be a "great opportunity" for David Moyes.

He wrote: "Fergie retires. What an act to follow. All the best to whoever picks up the gauntlet. Looks like Moyes. Big loss for EFC but great opportunity."

UPDATE! We have some more interesting quotes coming from chief executive David Gill with regards to Ferguson's replacement.

He told MUTV: "We have to look forward now and I think any manager coming in will inherit a great squad and great staff around him. It is a dream job. I won't speculate on the announcement but I think we will move relatively quickly.

"In Sir Matt Busby and Sir Alex we got in managers who got involved in all aspects of the club. That degree of loyalty is crucial to the success of Manchester United. [The next manager] needs the required football experience in terms of domestic and European requirements, so it is a small pool."

UPDATE! It seems as though things are moving swiftly in the Manchester United offices. Sky Sports News are reporting that news on Ferguson's successor could be announced as early as this afternoon! So, Moyes, Mourinho, Klopp? It may not be long until we find out.

So, let's delve into Gill's comments. Of course he has not mentioned any possible contenders but the fact that "European requirements" are on the list, suggests that Moyes does not fit that profile. So, who could that leave? Mourinho has a wealth of experience in Europe, not to mention guided Porto and Inter Milan to Champions League glory. Borussia Dortmund boss Jurgen Klopp has also been touted as a possible contender. The German boss will take his side to the Champions League final against Bayern Munich later this month.

The United players have arrived at Chester Races. TV cameras have shown Robin van Persie and Wayne Rooney walking along wearing sunglasses, with Ashley Young hobbling behind on crutches. No members of the team have made a comment regarding Ferguson's departure.

We have more Twitter reaction - this time from former boxer and Manchester City fan Ricky Hatton: "Can't believe I'm saying this seeing as the man was a thorn in our side for so long but what a manager Sir Alex Ferguson was."

Former United goalkeeper Edwin van der Sar has revealed that he is struggling to come to terms with Ferguson's exit. He tweeted: "Was coming for some time now but still a shock that hasn't sunk in yet. Great manager and remarkable person."

UPDATE! According to Sky Sports News, Everton are unaware of any reported interest from United in David Moyes, who has just left the club's training ground at Finch Farm.

UPDATE! Reports have claimed that Borussia Dortmund have moved quickly to quash suggestions that United could appoint Jurgen Klopp as Ferguson's successor.

Sky News journalist Paul Kelso has tweeted: "Borussia Dortmund say Jurgen Klopp will not be succeeding Sir Alex Ferguson at #MUFC. 'He has always said he will stay until 2016'"

West Ham United boss Sam Allardyce, who met Ferguson 45 times as manager, has had his say on today's massive news. The coach told the Hammers' official website: "I spoke to Sir Alex recently and I had no inkling that he was considering retiring from his position at Manchester United. So, like for everyone else, it has come as a bit of a shock.

"I think it's clear he was going to announce this at the end of the season, but whispers have got out somewhere, so he probably had to make it official right now."

More from Allardyce: "For himself, his wife Kathy and the rest of his family, I hope they can enjoy his retirement, the time they will have together and see things they have always wanted to see. Sir Alex has had an unbelievable career, not just at Manchester United, but when he first started [at Aberdeen in Scotland].

"For me, he is the greatest club manager that has ever been produced, certainly in this country, if not Europe. However many managers there were before him, the huge task he had was to achieve what Sir Matt Busby had done before him. For him to have done that and more, to have won the treble for Manchester United, and the joy and satisfaction of doing that gave was fantastic."

UPDATE! According to The Independent Real Madrid boss Jose Mourinho was NEVER a contender for the United job and is expected to return to Chelsea.

Journalist Sam Wallace wrote on Twitter: "#MUFC sources say Mourinho was never in the running to succeed Ferguson. As far as they're concerned his deal with #CFC is done & dusted ..."

Meanwhile, The Times are reporting that David Moyes will be appointed as Ferguson's successor within the next 24 hours.

So, Moyes has been mentioned a lot today, but there has been no word from Everton over the Scotsman, who comes to the end of his contract in the summer, being the next United boss. Sky Sports News are claiming that the 50-year-old is en route to London to watch Chelsea's clash against Tottenham Hotspur this evening. A trip that was already planned.

England manager Roy Hodgson has described Ferguson's decision to step down as a "sad day" in football. Hodgson came up against the Scottish boss numerous times during his stint as a Premier League manager. He said: "The unexpected news this morning that Sir Alex Ferguson has decided to retire marks the end of an era in football management.

"No one will be able to match his achievements, his dedication, his support for colleagues in need and his team building know-how. This is a sad day for English football. I personally wish him a happy and successful retirement."

Who knew that five months ago when the club unveiled a statue of Ferguson that the Scottish boss would retire from the game by the end of the season.

Here's a reminder of the ceremony at Old Trafford:

UPDATE! the Daily Mail are the latest publication to report that David Moyes will be announced as Sir Alex's successor tomorrow once personal terms have been agreed.

According to BBC Sport, the United players, whom the majority of are attending the Chester Races today, were informed at training this morning the identity of their new manager. The majority of reports are claiming that the manager in question is Moyes.

Former Arsenal and Manchester City midfielder Patrick Vieira has paid his own tribute to the legendary boss on Twitter: "It is the end of an era for a truly great ambassador, not only for the Premier League but for football overall. Best of luck to Sir Alex."

A man who has been linked with a switch to the Premier League, Atletico Madrid star Radamel Falcao, has called on everyone to show their appreciation to the outgoing Manchester United manager.

He wrote on Twitter: "Stand up, put your hands together and give him a big round of applause! Sir Alex Ferguson is retiring. Congrats for an amazing career!"

Sir Bobby Charlton, who was one of the directors who appointed Ferguson in 1987, has spoken of the Scottish manager's dedication.

"He is such a fantastic manager," the Daily Mail quotes Charlton as saying. "Everything he has done has been fantastic. He is a sensational person in every form and I am really delighted for him.

"I am a director but I hardly do anything because we are winning all the time and it is all down to Sir Alex Ferguson. He would get up in the middle of the night and travel 300 miles if he thought there was a school boy that he could sign. He loves the game and we at the club have had nothing to do really."

Charlton has also suggested that Ferguson's decision was partly down to health issues. He added: "He has made his decision on various grounds like his family and because of the hip operation he will have this summer."

United legend Denis Law has expressed his shock in today's huge announcement: "I was extremely shocked," the Daily Mail quotes Law as saying. "I couldn't believe it. I was with him only last week in Manchester. I always thought he would go on until 90 and then say: 'that's it'. He's too young to retire."

Ex-United captain Bryan Robson has hailed Ferguson's achievements over his 26-year stint as manager. "He has probably got to be the best club manager there has ever been," Robson told BBC Sport.

"It is unbelievable to change around probably four different squads and have the success he has had and rebuild a team like that - that is really good management and it is a difficult management skill to achieve."

"He will always be the boss to me, you don't think of him as Sir Alex it has always been the boss."

Former Everton and current New York Red Bulls midfielder Tim Cahill has admitted that Ferguson was one of the most "influential" men in football that he has ever met.

The Australian wrote on Twitter: "Sad day for football. The Great Man retires. One of the greatest managers ever. SAF is 1 of the most influential people that I have met #KING"

The New York Stock Exchange, where Manchester United are listed, opened at 2.30pm BST today and after the first 10 minutes of trading, the club's share price has dipped by 5% following news of Ferguson's departure.

The Daily Mail have attempted to provide some insight into today's meetings at United's Carrington training ground. The newspaper has claimed that the Scotsman was close to tears when he informed his players and staff that he was stepping down from the club. It is believed that Ferguson set up three separate meetings with his first-team squad, his coaching team, and the remaining staff.

While it has been reported that Ferguson decided against attending the Chester Races with his players, Michael Owen has told BBC Sport's Cornelius Lysaght that he hopes to meet up with him.

"He is just a couple of boxes down from me so I am going to hopefully have a drink with him later," Owen is quotes as saying. "He is arguably the greatest manager to have ever lived and to say I played under him for three years is a proud thing to say."

So, there we have it. Sir Alex Ferguson has finally decided to call time on his illustrious career at Old Trafford and will move upstairs as a director and ambassador of the successful football club. The Scotsman, who is 71, has claimed that it is the "right time" to leave his post, with some reports claiming that this summer's hip operation played a factor in his decision.

While there has been no confirmation who will succeed Ferguson, widespread reports have suggested that Everton manager David Moyes is in pole position ahead of the likes of Jose Mourinho to take the hotseat at the North-West outfit next season. Despite reports that Moyes could be installed as United boss as early as tomorrow, there has been no comment from the Merseyside outfit.

Whoever does become Ferguson's successor, I think it's safe to say that nobody will be able to match the Scotsman's career of 38 trophies, including 12 Premier League titles, five FA Cups and two Champions League triumphs. Thank you for joining me throughout the day, but make sure you stick around on Sports Mole for all the latest developments surrounding Old Trafford.