Terence Joseph "Terry" Nation (8 August 1930 - 9 March 1997) was a Welsh television writer and novelist. Nation first made his name as a comedy writer before becoming a prolific writer for drama, working on many of the most popular British series of the 1960s and 1970s. He made a significant contribution to the long-running BBC science-fiction series Doctor Who from its outset, creating the villainous Daleks which established its early popularity and later devising the recurring character of Davros.

Having returned to writing for Doctor Who, the BBC commissioned Nation to create a new science-fiction drama series. First broadcast in 1975, Survivors is the post-apocalyptic story of the last humans on Earth after the world's population has been devastated by plague. Although the series was well received, Nation's creative vision conflicted with that of producer Terence Dudley, and the final two seasons were produced without Nation's involvement.  Meanwhile, screenwriter Brian Clemens claimed that he had related the concept for Survivors to Nation in the late 1960s, having registered it with the Writers' Guild of Great Britain in 1965; Nation denied the allegations. Although the case was ultimately brought before the High Court, both sides withdrew from the proceedings after their legal costs mounted.  The production of Nation's next BBC creation, Blake's 7, experienced fewer problems. This series follows a group of criminals and political prisoners who are on the run from the evil "Terran Federation", piloting a stolen spaceship of unknown origin. Running for four seasons from 1978 to 1981, Blake's 7 acquired a worldwide fan following, and proved especially popular in Britain.  Although Nation scripted the whole of the first season of Blake's 7, his creative influence subsequently declined in the following two seasons despite writing some key episodes, as script editor Chris Boucher exerted a greater influence on those seasons. Nation didn't write any episodes in the fourth season of Blake's 7. In the 1980s, Nation attempted, without success, to secure funding for a fifth season of Blake's 7. During the 1970s, Nation wrote a children's novel for his daughter Rebecca (after whom he named the character of Rebec in the 1973 Doctor Who serial Planet of the Daleks) titled Rebecca's World: Journey to the Forbidden Planet, as well as a novel based on Survivors.

why did he decline?