The Belgian defender opted to sign for the Spaniards despite talk that he’s agreed personal terms with the Red Devils after lengthy negotiations between the sides.
Van Gaal has made the former Gunners captain his top target as he looks to rebuild his backline at Old Trafford, and even submitted a ‘name your price’ offer to the Londoners in a bid to get a deal done.
But Arsenal were reluctant to do business with a rival and Vermaelen made Barca his preference as they offered him a five-year deal.
Van Gaal has been left reeling by the episode, as he believed that he could keep the classy enforcer in England – a country he now has close ties to following a lengthy period at the Emirates Stadium and his long-standing relationship with his British girlfriend.
The Dutchman is thought to be back to square one in terms of backline recruits and could move for Mehdi Benatia of Roma of Ajax and Holland utility man Daley Blind.