The 71-year old finally announced on Wednesday night he will be stepping down as manager of the world’s biggest club.

Speculation grew at a fever pitch in the preceding 24 hours that an announcement by the Scot was imminent but it was only confirmed by a brief message from the club’s official Twitter account.

Soon after, Ferguson released a statement on the club website, outlining his decision to depart Old Trafford.

‘‘The decision to retire is one that I have thought a great deal about. It is the right time,’’ Ferguson said.

‘‘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.’’

Ferguson added he was further delighted  the club had developed world-class infrastructure under his tenure and that he was looking forward to continuing in his new capacity as a director and ambassador.

‘‘Our training facilities are amongst the finest in global sport and our home Old Trafford is rightfully regarded as one of the leading venues in the world,’’ he said.

‘‘Going forward, I am delighted to take on the roles of both director and ambassador for the club. With these activities, along with my many other interests, I am looking forward to the future. I must pay tribute to my family, their love and support has been essential. My wife Cathy has been the key figure throughout my career.’’

Bookmakers have already installed Everton manager David Moyes as an even-money chance of taking over from Ferguson, with Real Madrid’s Jose Mourinho considered the next most likely, though he is widely expected to return to Chelsea next season.

Ferguson’s decision will mean Australian fans will be one of the first to get a glimpse of the new Manchester United  manager in the Red Devils’ friendly match against the A-League All Stars on July 20 at ANZ Stadium.

However, having opted out of the 1999 tour, it will mean that local fans will never get to see Ferguson in charge of the famous club on Australian soil.

The club, which is owned by the American Glazer family and listed on the New York Stock Exchange, did not immediately announce a successor. Ferguson reversed a previous plan to retire at the end of the 2001-02 season.

After United secured their latest Premier League title two weeks ago – extending the club’s record English championship haul to 20 – Ferguson declared that he had no retirement thoughts.

But now he has just two more league matches left in charge of the club he has turned into one of the world’s biggest sports powers. Ferguson has previously said only health problems would force him to relinquish the job, and it emerged at  the weekend that he requires hip surgery. However, the retirement statement did not mention health issues.

He defined the modern era of success at United, resuscitating the fortunes of a club that was floundering when he arrived more than a quarter of a century ago, having won a European title at modest Aberdeen in Scotland.

While it took time for Ferguson to impose his leadership at Old Trafford, directors showed a degree of patience rarely afforded to current managers.

Ferguson eventually produced his first trophy in 1990 – the FA Cup – and in 1993 the club won its first top-flight title since 1967.

Since then, he has turned United into a European power and one of the world’s wealthiest sports clubs.

As well as Champions League titles in 1999 and 2008, United have  also won four League Cups and the 2008 FIFA Club World Cup.

Now United will have to plan for a future without Ferguson in the dugout.

‘‘We knew that his retirement would come one day and we both have been planning for it by ensuring  the quality of the squad and club structures are in first-class condition,’’ chief executive David Gill said.

with AP

Alex Ferguson's record at Manchester United:

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

Champions League: 1999, 2008

Cup Winners Cup: 1991

FIFA Club World Cup: 2008

UEFA Super Cup: 1992

Inter-Continental Cup: 1999

FA Charity/Community Shield: 1990 (shared), 1993, 1994, 1996, 1997, 2003, 2007, 2008, 2010, 2011