Mr. and Mrs. Mason
Uncle Vernon invites Mr. and Mrs. Mason to Number 4 Privet Drive to make a deal for a major drill sale for his company, Grunnings. It turns out, unfortunately for Uncle Vernon, that Mrs. Mason has a terrible fear of birds. When Harry receives some unexpected owl post during the Dursleys' dinner party, that finally destroys any chance Uncle Vernon might have had to make the deal successfully. It's on the pretext of this failed deal with Mr. Mason that Uncle Vernon locks Harry in his bedroom in Chapter 2.