Cresswell had great "popular impact" because she "diversified into writing for television, in 1960, with a script for what was then called "Jack Playhouse", bringing simple storytelling to BBC children's TV." She tried writing for adults but succeeded with the child audience. Her first book was published in 1960, "Sonya-by-the-Shore", and the Jumbo Spencer series followed. Yet she considered herself a poet until "The Piemakers" (Faber, 1967) won both "success with young readers" and approval from critics. It was a commended runner-up for the Carnegie Medal from the Library Association, recognising the year's best children's book by a British subject.