Willo the Wisp beech wood in Oxfordshire, near the director's home. Kenneth Williams provided voices for all of the characters. The principal narrator, Willo the Wisp, was a blue, floating creature drawn as a caricature of him, while the name refers to the ghostly light will-o'-the-wisp from folklore. The other main characters were Arthur the caterpillar (as a gruff cockney), Mavis Cruet, a plump, clumsy fairy with an erratic, magic wand, and the principal antagonist, Evil Edna, a witch in the form of a walking, talking television set who could zap people with her aerials. Other characters included Carwash, a snooty bespectacled cat
Mavis Wilton Street's" best-loved characters, describing her as timid and "clad in sensible cardigan and shoes". Jules Stenson writing in "The People" said that Mavis was much like the previous character Minnie Caldwell (Margot Bryant): they were both "easily bullied" and, like Minnie, Mavis seemed to be "on the shelf for life" until her marriage to Derek. In Meade's opinion, Mavis gave a name to and represented a certain type of woman: "A 1940s spinster with a 1940s head who's looked 50 since birth. A "Woman's Realm" made flesh. And you have a name for her. She's a Mavis ... Mavis Riley