The film was the idea of writer Beverley Cross.[10] In 1978, Andor Films submitted a copy of the script to the British Board of Film Classification, seeking advice on how to secure either a "U" or an "A" certificate. The draft script included scenes which the BBFC considered would be unacceptable under those certificates, including the Kraken tearing Pegasus to pieces and Andromeda appearing naked during the climax of the film. Changes to the script and, on submission, some cuts to Perseus's final battle with Calibos were made and the film secured the "A" certificate: "Those aged 5 and older admitted, but not recommended for children under 14 years of age".[11]