Writer, Producer, and Director Jonathan Miller explained that the reason that none of the actors or actresses (even those playing non-human characters) wore costumes aside from Victorian period dress, was that he thought it was ridiculous to get big name stars to play parts (as he did in this movie and MGM had done in Alice in Wonderland (1933)) and then cover them up in big costume animal heads so they were unrecognizable.
Most of this movie was shot with a 9mm camera lens.
Jonathan Miller's son attended the opening of an Alice exhibition at the V&A in 2021, where a 2-minute clip of the tea party is shown. He admitted his father had no interest in making Alice as a children's film, he saw it as a piece about mental illness.
Writer, Producer, and Director Jonathan Miller chose Anne-Marie Mallik to play Alice, because she had an appropriate sense of Victorian solemnity about her.