Sir Alex Ferguson didn't want David Beckham to wear the No.7 shirt at Manchester United, according to Roy Keane. Beckham sported the famous jersey at Old Trafford and with England between 1997 and 2003, becoming his trademark number.
Beckham was first awarded the No.28 at United when shirt numbers were introduced in the Premier League in 1993-94, swapping it for the No.24 two years later. He was then awarded the prestigious No.10 ahead of 1996-97 after solidifying his place in the team.
Eric Cantona wore the No.7 at Old Trafford during the Premier League's early years, but the shirt became available on the Frenchman's retirement in May 1997. The No.7 then belonged to Beckham for the foreseeable future, but only after Keane's intervention.