Manchester United manager Sir Alex Ferguson has revealed that he made his decision to retire "last Christmas".

The 71-year-old Scot, who has been at the club since 1986, took charge at Old Trafford for the final time on Sunday as the Red Devils beat Swansea City 2-1 in the Premier League.

Ferguson bows out of the game with nearly 50 major honours to his name, including 13 Premier League titles, two Champions Leagues and five FA Cup triumphs.

"I decided to retire last Christmas," Ferguson told BBC Sport. "Things changed when my wife Cathy's sister died. She has lost her best friend, her sister. Also, I wanted to go out a winner.

"I've got a lot of things to do. My son Jason's been organising things. I won't be sitting still."

Ferguson will oversee his final game for United next Sunday when they travel to West Bromwich Albion.