Billington worked in television in London and New York before taking up full-time writing in 1968. She has published twenty-one novels for adults, including the bestsellers "A Woman's Age" and "Bodily Harm". Her novel "Glory" (2015) describes the First World War Gallipoli campaign through the eyes of the participants and their wives and girlfriends at home. She has also written six children's novels, six religious books for children and three non-fiction books, including "The Great Umbilical", about mothers and daughters.