In the list “Accent-uate the Negative,” MSN unveils some of its choices for “the 10 all-time worst movie accents.” Included in the list is Dick Van Dyke’s performance in Mary Poppins. Nonetheless, the article admits, “Granted, in the ’60s, the idea of a screen actor, let alone a renowned comedian like Van Dyke, actually working to make his character’s accent believable was something of a novelty. And no way could any of them have guessed that videotapes and DVD would arrive to put their shoddy work on display for all time.”
Poppins performance among "worst movie accents"