Doctor Who: Vengeance on Varos (1985) by Philip Martin
The TARDIS is acting up again, so Sixth Doctor (Colin Baker) and his companion Peri (Nicola Bryant) have to find a special fuel, Zeiton 7 ore, otherwise they'll be stuck drifting in empty space forever. One last burst of energy gets them to the planet Varos, only source of the ore which the TARDIS needs. The only problem is Varos was a penal colony, so the local laws are quite harsh. People are punished severely for infractions and these punishments (including executions) are broadcast for the entertainment of the Varosians. The governor of Varos is in negotiations with Sil, alien representative of the Galatron Mining Corporation, which seems to have some exclusive deal on exporting Zeiton 7. Sil wants the cheapest price possible, the governor wants his people not to starve. The Varosians don't realize the high value of their ore (it's used in all time and space travel) so they vote against the governor when he asks them to hold out via TV broadcast. Whenever one of his proposals is voted down, he gets tortured on TV just like any criminal, which may partially be motivating negative votes. Also, the governor and his advisors are considering exporting videos of the punishments as a secondary source of income, another negotiation point with Sil.
The plot is quite serious for a Doctor Who story and a fairly early condemnation of reality TV (thought it does come two years after David Cronenberg's Videodrome and copies parts of that movie). The ideas are interesting but the lack of humor and lightness is noticeable (except for the campy corporate conniver Sil). Colin Baker's Doctor is rather dark and dour in spite of wearing the most flamboyant outfit in the series. He's perfectly willing to let baddies die (two of the guards wind up in an acid bath!) and bickers with his rather pleasant companion (though her American accent is dodgy at times). The darkness seems to be more in the writing than the actor. I'd be interested to see other Colin Baker episodes to find out if that's true or not.