SIR ALEX FERGUSON has dominated English football for over 26 years. Now, having decided to call it a day, 20/13 pays tribute to the man's remarkable achievements by recounting each of Manchester United's 20 title triumphs from the Edwardian era to the present day and the 13 titles won by Sir Alex during his United reign. The signing of Robin Van Persie provided the last great coup of the Ferguson era, the Dutchman shunning Manchester City in favour of Old Trafford following a summer long transfer chase. Sure enough, Van Persie went on to earn a second successive Premier League Golden Boot and with the league title he craved. Yet 20 is about more than just United's most recent triumph. Award-winning journalist Harry Harris looks back at every title winning season and analyses each one from the viewpoint of a player who distinguished himself in that title year. It is a tribute to Sir Alex Ferguson that the future of English football suddenly seems unpredictable without the last great football manager and the power and influence he wielded within the game.