I did a google about mary poppins and it actually turned up a very interesting result: a short paper from 2014, "The Subversive Mary Poppins: An Alternative Image of the Witch in Children’s Literature" which has some seriously good stuff:
The literary Mary Poppins was a different creature and her task more mysterious. Travers‘s Mary Poppins is not sweetly helpful or simply good; she was supposed to be a witch, with all the power that the term implies.
Travers studied world mythology and mysticism, and brought a wealth of knowledge to the undertaking. She did not think of her witch in terms of the stereotype that has come down to us from the Middle Ages, the wicked witch in a pointy hat who eats children. Travers saw Mary Poppins as an even more ancient type of witch – a pre-Christian version of a powerful, magical woman, a priestess to older gods and goddesses, a medicine woman communing with the spirits of animals and plants, tuned into the magic of the natural world.
So now I've got to read those books I guess
