A for Andromeda
The original BBC tv versions have been mostly destroyed, and Christie was not signed up for the sequels. When the sequel was written, Christie had become too expensive for the BBC to hire again. At that time the BBC did not perhaps understand the concept of "property rights", an important part of the modern world. Media creations are properties. Property is not to be thought of as just buildings: any creative act is potentially a property in the sense of copyright.