The Belgian defender looks set to leave the Emirates Stadium in the coming weeks after enduring a tough 2013/14.
Despite being the Gunners’ captain, Vermaelen barely featured last term, with Arsene Wenger electing to partner Per Mertesacker and Laurent Koscielny at the heart of his backline.
With the silky centre-back eager to leave, United have stepped up their pursuit as they look to replace the departed Rio Ferdinand and Nemanja Vidic – who have been first-team regulars for the last 10 years.
It is understood that an agreement regarding personal terms has been reached with the player, leaving only a fee to be paid to Arsenal in question.
The Londoners are aware that they must sell this summer with Vermaelen now in the last year of his contract, and are looking to get in around £10m-£11m from their rivals.
United started the Louis van Gaal era by snapping up Ander Herrera and Luke Shaw for £60m late last week.