The 28-year-old was a Manchester United target and Arsene Wenger confirmed a bid from United but having moved to Barcelona, Louis van Gaal will have to look elsewhere for a new defensive signing.
Vermaelen is the sixth player to join Barcelona this summer after Ter Stegen, Rakitic, Bravo, Suarez and Mathieu.
Van Gaal has admitted United are in the market for defenders this summer after the departures of Nemanja Vidic and Rio Ferdinand and Vermaelen’s move means United’s focus is elsewhere.