The series was an adaptation of The Devil's Children - the first of three novels in The Changes trilogy by author Peter Dickinson which also included Heartsease and The Weathermonger.
The Changes was broadcast in ten parts every Monday from 6th January to 10th March 1975.
Filming took place over the summer of 1973.
The series was shot in the West Country, namely Bristol, the Forest of Dean and Sharpness.
Although playing a schoolgirl in her early teens, Victoria Williams celebrated her eighteenth birthday during filming.
Theme and incidental music composer Paddy Kingsland went on to score both the radio and TV adaptations of The Hitchhiker's Guide to the Galaxy for the BBC. He also provided incidental music for a number of Doctor Who stories in the early eighties.