Iain Harvey, the film's executive producer and publisher at Hamish Hamilton, recalls that the book had initially sold well, but a second print had been less successful with 50,000 unsold copies sitting in a warehouse, which he attributes to the lack of dialogue preventing it being read as a bedtime story. In 1980 he was contacted by producer John Coates from TVC (Television Cartoons) with an idea of adapting the book for an animated film, for which he gave his consent.
