"Heidi" by Johanna Spyri was published in 1881. This TV Serial was the BBC adaptation of "Heidi". It is the most faithful to the classic, including some of the actual dialogue and dramatizing the narrator's notes. Despite, or because of, this it remains relatively unknown.
This was one of two British adaptations of Heidi, the first being in 1959 and the second, this serial, in 1974.