Sylvia Anderson first episode of a series then sharing the work according to their strengths. Gerry tended to specialise in special effects and hardware, and Sylvia in character, voices, costume, dialogue, and plotlines. In this way, Anderson contributed plot development and voice work for a series of half-hour shows including "Supercar", "Stingray" and "Fireball XL5". However, she felt the half-hour format was insufficient to fully develop characters and stories, and she persuaded the team's TV producer Lew Grade to extend their shows to a full hour. In the early 1960s, the Andersons co-created the series "Thunderbirds", and Sylvia created the characters. She
Gerry Anderson his goal of making live-action film and TV drama. During the production of "The Adventures of Twizzle", Anderson started an affair with secretary Sylvia Thamm and ultimately left his wife and children. Following his divorce from his first wife, Anderson married Thamm in November 1960, while he was working on "Four Feather Falls". AP Films' third series was the children's western fantasy-adventure series "Four Feather Falls" (1959–60). Provis left the partnership, but the company retained the name AP Films for several more years. "Four Feather Falls" was the first Anderson series to use an early version of the so-called "Supermarionation"