We considered five other top managers before David Moyes, says Sir Alex Ferguson

Ferguson reveals in his new book, 'Leading', that he looked at Jurgen Klopp, Carlo Ancelotti, Pep Guardiola, Louis van Gaal and Mourinho - "a spectacular manager" - as potential replacements, but they had all committed to other projects by the time the Scot had decided to retire.

"I asked Pep to phone me before he accepted an offer from another club but he didn't and wound up joining Bayern Munich in July 2013," Ferguson wrote.

"When we started the process of looking for my replacement, we established that several very desirable candidates were unavailable.

"It became apparent that Jose Mourinho had given his word to Roman Abramovich that he would return to Chelsea, and that Carlo Ancelotti would succeed him at Real Madrid.

"We also knew that Jurgen Klopp was happy at Borussia Dortmund and would be signing a new contract. Meantime, Louis van Gaal had undertaken to lead the Dutch attempt to win the 2014 World Cup," he added.

So, after he had told the club’s owners, the Glazers, about his decision to step down, they started looking elsewhere for a new manager.

Ferguson added: “Once I’d conveyed [my retirement] to the Glazers, then the process started of looking for successors. We chose David Moyes. He had been consistent in his job at Everton, had a good spell there — 11 years and showed appetite. No one knew apart from the Glazers, David Gill and myself.

“When we appointed him, the press were enthusiastic for a British manager. Unfortunately, somehow it didn’t work out for David. The process was perfect. It was a good process.”

However, the Scot insists he always gave Moyes his support following his appointment, and is fully behind current boss Van Gaal.

"I just wanted David and United to win - just as I do these days with Louis van Gaal," said Ferguson, who claimed TV cameras are now trained on him in the directors’ box at every United match.

"I think they hoped they would catch me acting like Statler or Waldorf, the two curmudgeons in the Muppets, who are always criticising what is happening on the stage."

Ferguson also recalls the first time he interviewed Moyes as a potential No 2 in 1998 - when the then Preston boss was overlooked and Steve McClaren took the position.

Moyes, Ferguson writes, was "very tense" during his interview with him following Brian Kidd's departure from United to Blackburn.

"Steve McClaren was the opposite of David," Ferguson added. "He was bright, breezy, and enthusiastic. At that point Steve had a lot more experience in the top flight of football than David and that swung my decision."

The man who Van Gaal has anointed as his successor, Ryan Giggs, gets a glowing reference from Ferguson in the book.

"Ryan Giggs is eventually going to be a great manager - he has intelligence, presence and knowledge," added Ferguson.