Decay (1980). State of Decay was in fact a re-written version of a story originally titled The Vampire Mutations, which had been due for production during season 15 until the BBC decided that the vampiric theme would clash with the plot of its new adaptation of Bram Stoker's Count Dracula, which was due for transmission at roughly the same time, and replaced it with Horror of Fang Rock. His final Doctor Who script was The Five Doctors (1983), a feature-length episode for the programme's 20th anniversary. His other work for Doctor Who included two stage plays, Doctor Who and the Daleks in the Seven Keys to Doomsday (1974) and Doctor Who - The Ultimate Adventure (1989), and an audio drama for Big Finish Productions titled Comeback (2002), which was the first to feature former Doctor's companion Sarah Jane Smith in a significant capacity. He went on to contribute several additional scripts to Big Finish including audio adaptations of his two-stage plays, a Sixth Doctor-era story for the "Companion Chronicle" range, and a Bernice Summerfield story, in 2011, which was the final script of his career. The first serial aired after his death, the 2020 Thirteenth Doctor-era story "Spyfall", was dedicated to him. Books Dicks contributed heavily to Target Books' series of novelisations of the Doctor Who TV serials, writing 67 of the titles published by the company. As Dicks explains in an interview in the documentary Built for War (included on the 2006 DVD release of The Sontaran Experiment), he served as the unofficial editor of the Target Books range. In this role, he would attempt to enlist the author of the original scripts to write the novelisation whenever possible, but if they refused or had other commitments, Dicks would usually undertake the work himself (although he also recruited other writers, including former Doctor Who actor Ian Marter and former series producer Philip Hinchcliffe). On one occasion, he enlisted Robert Holmes to novelise his script for The Time Warrior, but when Holmes gave up after writing only one chapter, it was left to Dicks to complete the work. Dicks would have better success in recruiting the original writers for the later Doctor Who serials, and was required to adapt only one Sixth Doctor story himself (The Mysterious Planet; he again replaced Holmes, who had died in 1986). Dicks' name appears on the cover of no Seventh Doctor novelisations. His plans