'Vengeance on Varos' (2 Parts) Story Code '6V' by Philip Martin

When the TARDIS loses power, the Doctor realises that it needs a quantity of the rare mineral Zeiton-7 to replenish its energy banks. He manages to use the last of the residual power to take the ship to Varos, a mining planet that is inhabited by the descendants of a colony for the criminally insane. The Governor and Chief Officer of the colony keep the workers 'entertained' by playing them a constant stream of violent images and public tortures of dissidents. Varos's Governor has been attempting to negotiate for better prices for the Zeiton ore with Sil, the worm-like envoy from the Galatron Mining Corporation. The Doctor and Peri help two rebels, Jondar and his wife, Areta, to escape, by avoiding the deadly traps in the Punishment Dome. But while the Doctor apparently dies in one of the Dome's many ambushes, the others are recaptured. Quillam, a sadistic scientist, places Peri and Areta in a transmogrifier machine and they are transformed into bird- and lizard-like creatures. The Doctor recovers from his injuries and escapes, only to be recaptured; believing him to be from a rival mining corporation, Sil forces the Governor to sentence the Doctor and Jondar to a public hanging. But the ceremony has been faked in order to reveal the Doctor's true intentions; the Time Lord convinces the Governor of the error of his society, reveals Sil's duplicity, and shows him the true value of the Zeiton ore. The Doctor, Jondar and the Governor rescue Peri and Areta, who are restored to normal. Quillam and the Chief Officer are revealed to be in Sil's secret employ; they attempt to kill the Doctor and the Governor, but are instead killed by one of the Dome's traps. Sil's plans to have the Galatron Company invade Varos are cancelled, and the Company instead offers to buy the mineral at any price. The Governor abolishes the planet's cruel political system, and ceases the transmissions.

Colin Baker (The Doctor), Nicola Bryant (Peri), Martin Jarvis (Governor), Nabil Shaban (Sil), Nicholas Chagrin (Quillam), Jason Connery (Jondar), Forbes Collins (Chief Officer), Stephen Yardley (Arak), Sheile Reid (Etta), Geraldine Alexander (Areta), Graham Cull (Bax), Owen Teale (Maldak), Keith Skinner (Rondel), Hugh Martin (Priest)

Produced by John Nathan-Turner
Directed by Ron Jones

TX:
Part 1 - 19th January, 1985 @ 5.20pm - 6.05pm
Part 2 - 26th January, 1985 @ 5.20pm - 6.05pm

Notes:
*Featuring the Sixth Doctor and Peri

*First appearance of Sil

*Working titles: 'Domain', 'Planet of Fear'

*Each part is 45 minutes duration

*This story was repackaged in 2023 in omnibus format under the banner of 'Tales of the TARDIS'; it was released on the BBC's iPlayer in the UK only, and had linking scenes featuring Colin Baker and Nicola Bryant portraying 'memory versions' of their original roles: 'The Doctor and Peri meet again and remember their conflict on the mining planet Varos: a world that entertains its people with sadistic TV broadcasts.' [Note: I don't consider this canon, so have not included it in the main story timelines]