Season 20 Season 20 of " Doctor Who " was Peter Davison ' s second season as the Fifth Doctor , and it ran between 3 January 1983 and 16 March 1983 . Before the season ended , Nyssa had departed , Turlough had arrived , and the Brigadier had returned . Every story of this season contained an old enemy of the Doctor in at least a minor role , to celebrate the twentieth anniversary of the show . Structurally , the season retread season 18 ' s formula of including a trilogy of stories bound together by an overarching theme . In this instance , the tripartite tale involved Turlough ' s attempts to kill the Doctor at the behest of the Black Guardian . Overview . Season 20 was notable for the degree to which it varied from its original plans . It had been commissioned as a 28 - part series , and the intent was that it would have actually been broadcast towards the end of 1982 . Producer John Nathan - Turner had hoped to use season 20 as a way to reverse the January - March broadast of season 19 . Thus , he had initially obtained permission to record and broadcast season 20 in 1982 , thus making season 21 broadcast over the milestone 23 November 1983 . Had JNT got his way , the " twentieth " anniversary special would have in fact been a part of the regular twenty - " first " season . Although this idea was in fact greenlit , permission had to be rescinded when it was discovered that Davison ' s second job — the then - popular BBC One comedy , — wouldn ' t allow for this more aggressive " Doctor Who " production schedule . BBC One controller , Alan Hart , had to personally step in to settle the dispute between the two production teams , and he " awarded " Davison to " Sink or Swim " . This meant that season 20 would , like its predecessor , be broadcast in the first quarter of 1983 . Hart , however , did want some sort of anniversary special in November , so he suggested that JNT put the money for two of the 28 episodes aside to allow for the special . This of course meant that there would now be 26 episodes in season 20 . In the end , however , the final four episodes — meant to go towards a Dalek adventure that eventually became season 21 ' s " Resurrection of the Daleks " — were left on the table because of a union dispute . Thus , as transmitted , season 20 consisted of just 22 episodes . Meanwhile , the anniversary special , which was originally envisaged as a part of season 21 , was something quite separate from " any " season . Although it used a portion of the original money involved in the season 20 commission , it received a separate commission from Head of Series David Reid on 15 July 1982 , long after season 20 had wrapped . Indeed , it only received this commission because JNT had been able to secure co - production money from the main Australian network . Moreover , " The Five Doctors " , as the production was eventually called , didn ' t begin principal photography until early March 1983 — just when season 20 was wrapping transmission on television . " The Five Doctors " , though often said to be a part of season 20 , was therefore not a part of season 20 in any production or broadcast sense . Indeed , it ' s doubtful that any contemporary viewer thought of it as a part of the season , since it came almost eight months after the closing scene of " The King ' s Demons " . Instead , it had much greater production and broadcast proximity to season 21 . Adaptations and merchandising . Home media . DVD . All serials of season 20 were released individually in between 1999 and 2011 , with " The Five Doctors " being the first ever serial released on DVD .