Alex Ferguson thanked tens of thousands of Manchester United fans as they massed to salute him and his final title-winning side on an open-top bus parade through the city streets on Monday. United manager Ferguson, one of world football’s most successful bosses, is retiring at the age of 71 after guiding the Red Devils to the English Premier League title for a 13th time. After arriving at Manchester Town Hall following the victory parade from United’s Old Trafford ground, Ferguson was seen singing fans’ favourite “Glory, Glory Man United” from the balcony. And he briefly took to a temporary stage below in the city’s Albert Square, which was packed with thousands of flag-waving supporters bedecked in the club’s red, white and black colours. In what was likely his final public address to his adoring faithful, the Scot said the jubilant scenes surpassed even those of 1999, when the northwest side completed an unprecedented trophy treble of the Premier League, FA Cup and European Champions League. “I thought 1999 would never be beaten but you have beaten it,” Ferguson said. Red streamers hung in the trees, coloured flares went off and people clambered all over monuments for a glimpse of the…