Sir Alex Ferguson admits one of his biggest mistakes at Manchester United was revealing that he would retire in 2002 before the season had finished.

The Scot subsequently reversed his decision to call time on his reign at Old Trafford but eventually retired in 2013 having won 38 trophies with the club.

“It's important to listen to your staff. In 2005, that period we didn't win anything, just before that I had an attempted retirement, and I think that affected everyone,” Ferguson told ESPN.

“It was a mistake, and my wife and my three sons changed my attitude towards it and I started to think.

“The biggest mistake I made was announcing it at the start of the [2001-02] English Premier League season, and I think a lot of them had put their tools away; they thought, 'Oh, the manager's leaving,' but when I changed my mind in the January, I started thinking about United again and how we could get back on top.

“After that is when [Wayne] Rooney and [Cristiano] Ronaldo came to the club and we had to regenerate everyone."

"The youth side of it, the scouts; we'd gone to sleep. Strangely enough, the period from there on has been glorious; it's been fantastic with the numbers of league titles we won."

“The moments you don't win anything register very strongly with Manchester United.”

Manchester United manager Sir Alex Ferguson (R) and Wayne Rooney embrace. Photo: AFP