Charlton, then a fresh-faced 16-year-old, had attracted the attention of the club's scouts and it was on 6 June 1953 he reported for his first day's work.
Bobby was taken on as an apprentice and, in between training sessions, worked with the ground staff to maintain the Old Trafford pitch. It was the beginning of one of the most successful careers in English football.
With United, Charlton won three league titles, the FA Cup and the European Cup in 1968, 10 years after surviving the Munich air disaster, a tragedy that claimed 23 lives, including eight of his team-mates and best friends. When Charlton ended his Reds career he was the club's leading scorer, with 249 goals (a record that still stands).
In his autobiography, published in 2007, Sir Bobby recalled his first days at Old Trafford.
"It seemed I had, after all, been given access to my idea of paradise. I had the friendship of great young footballers who were ready to accept me and so clearly shared my passion to play the game that had always been an inspiration. The days stretched ahead of me so excitingly."