The 18-year-old left-back established himself as one of the hottest prospects in world football during his time at St Mary's, leading to admiring glances from many major clubs.
However, it is United that have won the race for Shaw's signature after he successfully passed a medical at the club's Carrington training ground on Thursday evening.
Press Association Sport understands the deal, which includes add-ons, is now complete - echoed by the player's Twitter account as, despite no official confirmation from either club, his biography now reads "Professional footballer at Manchester united Football Club".
Source : PA
Source: PA