[[quoteright:350:http://static.tvtropes.org/pmwiki/pub/images/maggots_6225.jpg]]
[[caption-width-right:350:This is an actual screenshot of a Doctor Who serial that contains a GreenAesop. [[NotMakingThisUpDisclaimer Seriously.]]]]
-> ''Stevens, listen to me. You've seen where this efficiency of yours leads. Wholesale pollution of the countryside. Devilish creatures spawned by the filthy by-products of your technology. Men... men walking around like brainless vegetables. Death. Disease. Destruction.''
-->-- '''The Doctor''' gets all eco-warrior

A Welsh miner is found dead, his skin glowing bright green. UNIT is naturally called in to the village of Llanfairfach to investigate. A local environmental group, led by Professor Clifford Jones, has been investigating the work of nearby Global Chemicals. The Doctor can't bring himself to care and goes on a nice holiday to the planet Metebelis III instead. Jo and the Brigadier pay visit to Global Chemicals. They discover that the mine workings are full of giant maggots and green goo, both by-products of Global Chemicals' plant. People at the company also have a tendency to get hypnotised and start rambling about "the Boss".

Metebelis III turns out to be the planet of EverythingTryingToKillYou, so the Doctor hastily rejoins the plot back on Earth, carrying a shiny crystal as a souvenir. He rescues Jo, who fell down a mineshaft, and discovers that the place is crawling with giant alien maggots.

Clifford, who's a charismatic long-haired DeadpanSnarker and lives in a hippie commune, also happens to be a genius biologist who's working on a revolutionary new fungus that could globally replace meat. He and Jo get along very well (after some initial mutual snarking). The Doctor is also a big fan of his papers, and soon enough, the whole gang is happily drinking fine wine and eating fungus. But with a whole lot of maggots still out there, UNIT decides to inflitrate Global Chemicals: Mike Yates as an office drone, and the Doctor as a Welsh milkman and a harmless old cleaning lady.

The plant is run by Stevens, who has been taken over by the intelligent computer BOSS (Bimorphic Organisational Systems Supervisor), which plans to seize power by linking to every other major computer in the world. BOSS was originally built by Stevens, became self-aware, and soon realised that human creativity is based on human error. He ordered Stevens to program human error into his system. Enjoying his new creative powers, and merrily humming Beethoven, BOSS toys with the Doctor a bit but can't even make a dent in his Time Lord psyche. The Doctor uses a large blue crystal he picked up on Metebelis III to break BOSS' hold on Stevens, and Stevens -- in a grand HeroicSacrifice -- programs BOSS to self-destruct. Meanwhile, the maggots, which are beginning to pupate into giant flies, are destroyed with Clifford's fungus.

In the midst of all this, Jo has fallen in love with Clifford, and decides to leave the Doctor to go get married and explore the Amazon rainforest (in that order). She pulls some strings with her uncle to get Clifford all the funding he'll ever need. As the whole group celebrates, the Doctor gives her the blue crystal as an early wedding gift, and leaves, sadly.

The planet of Metebelis III will become important again [[Recap/DoctorWhoS11E5PlanetOfTheSpiders soon enough]]. And Jo will meet the Doctor again, although much, ''much'' [[Recap/TheSarahJaneAdventuresS4E5E6DeathOfTheDoctor later]].

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An excellent tongue-in-cheek {{Mockumentary}} sequel, "Global Conspiracy", was created by Creator/MarkGatiss in 2004 and stars most of the original cast.

!!Tropes
* AbsentMindedProfessor: Clifford.
* AIIsACrapshoot: An interesting take on this in that the computer has actually been ''programmed'' by Stevens to be a megalomaniac, as BOSS noticed that humans often achieved their goals better through being illogical.
** BOSS was programmed with the objectives of maintaining productive order and ensuring profit for Global Chemicals. It just interpreted those objectives in an extremely broad and amoral manner.
* AuthorTract
* BBCQuarry: But this time, it actually is a quarry!
* BlatantLies: Stevens to Elgin. "Don't worry- I won't hurt you."
* TheCaligula: BOSS has shades of this.
* ChekhovsGun: There are two: the sapphire from Metebelis III, and the hybrid fungus that Clifford Jones was raising as a meat substitute. The dried spores of the fungus cures Clifford Jones of his own infection from the Green Death later on, while clumps of the fungus kill the maggots.
* CorruptCorporateExecutive: Stevens.
* DisguisedInDrag: Third Doctor actually does this... as a cleaning lady.
--> '''The Doctor''': (having finally met up, in disguise and carrying a bucket, with Mike Yates) If you say one word...
--> '''Mike Yates''': I like your handbag.
* DisneyVillainDeath: Poor Fell.
* DoppelgangerDating: Clifford is basically the Doctor, only younger and less asexual. His MeetCute with Jo (she wanders into his lab and gets yelled at for ruining an experiment) is even a reprise of her first meeting with the Doctor.
* DrivingADesk: Although the maggots are very well-made, this episode also features [[SpecialEffectFailure some of the worst greenscreen in television history]].
* EruditeStoner: Most of the people at Cliff's research facility, but especially Nancy. Shown in a completely positive light without any hint of sarcasm.
* FindTheCure: Much of the plot is devoted to searching for a cure the eponymous Green Death.
* FourthDateMarriage: Jo and Cliff.
* GreenAesop
* HypnoFool: The Doctor uses his Metebilis crystal on Mike to break BOSS's mind control by using a counter-hypnosis. Too bad the Brigadier was staring at it while the Doctor was doing so. He goes into a thick trance, stiff as a board.
-->'''Doctor''': Oh, ''good grief!'' Wake up, Lethbridge-Stewart! ''(gibbers the Brig's chin)'' Wake up!
* IKnowYoureInThereSomewhereFight: The page quote is part of one.
* ImmuneToBullets[=/=]NighInvulnerability: The maggots... bullets, bombs, and even insecticide don't even phase them.
* ImprobableAntidote: The cure for the eponymous death turns out to be the dried spores of the fungus Professor Jones is working on as a solution to world hunger.
* IronicName: The last name of Ralph, the worker conditioned to self-destruct by jumping to his death, is "Fell". How did Ralph die? [[IncrediblyLamePun Ralph Fell]].
* JanitorImpersonationInfiltration: The Doctor disguises himself as a cleaning woman.
* LampshadeHanging: By this point, the Doctor is less than impressed by the revelation that the real villain is a crazy computer.
* {{Leitmotif}}: BOSS has a militaristic and tyrannical-sounding incidental music sting that plays whenever he's plotting something megalomanical or his handiwork is seen in action.
* LogicBomb: Subverted. The Doctor tries to use the Liar Paradox on BOSS, but BOSS completely fails to blow up, stop working, or devote all its circuits to solving the problem. It's just mildly annoyed for a while.
* TheManBehindTheMan: Up until BOSS is revealed to be a computer controlling the entire building, he is treated like this by the story. Stevens only communicates with him by office intercom and we're never given any indication he's anything but a corrupt human executive - "the boss," just as everyone keeps calling him. Then when the Doctor gets to the top floor where "the boss'" office supposedly is, only to find loads of computer equipment... we get the WhamLine.
* MasterComputer: BOSS is one of these.
* MoodWhiplash: It ends with everyone congratulating Jo and Cliff, including the Doctor... who then quietly leaves the party and drives off on his own.
** Also, the shocking scene of Fell leaping to his death is immediately followed by... a party at the Nut Hatch.
* NamesToRunAwayFromReallyFast: ''Don't'' name your intelligent supercomputer "BOSS"; it'll give it ''ideas''.
* NotHimself: Those under the control of the BOSS.
* NotListeningToMeAreYou: Jo offers Cliff a cup of tea... coffee... arsenic...
* NotThatKindOfDoctor: Professor Jones.
* OOCIsSeriousBusiness: A subtle one - Elgin notices something is up with Ralph Fell because he calls him by his last name. Apparently they're usually on a first name basis.
* OrphanedPunchline: The Doctor tells a joke that ends with the line "Never trust a Venusian shanghorn with your perigosto stick."
* PoorCommunicationKills: If only Professor Jones used an easier word than ''serendipity'', Jo would have understood him and known that the fungus was the cure for the maggots' bite.
* RedemptionEqualsDeath: Stevens.
* RousseauWasRight: Professor Jones honestly thinks that they can ask Global Chemicals to let them borrow cutting equipment to fix the Llanfairfach mine elevator. The same Global Chemicals he and the rest of the denizens of Wholeweal have been protesting and verbally chastising every other day.
* SicklyGreenGlow: Every victim of the "[[MeaningfulName Green Death]]".
* SingleTear: Poor Stevens cries a single stream of tears after shutting off BOSS and awaiting his imminent death, coupled with a MyGodWhatHaveIDone reaction.
* StrawmanPolitical: Played both straight and averted in Global Chemicals. While Stevens is a megalomaniac who is just fine with completely destroying the environment and unleashing a biological horror upon Wales if it'll raise Global Chemicals' stock price a tuppence a share, and BOSS is worse, most of people under Stevens, including the [=VPs=], are decent hardworking people who want to do the right thing and basically have to be brainwashed by BOSS to go along with the program.
* TemptingFate: [[LampshadeHanging Lampshaded]]. The Brigadier thinks blowing up the mine has solved the maggot problem. He says, "I don't understand you lot. Seems to me the problem's solved. We'll see no more of those creepie-crawlies, you mark my words." Everyone looks at him like he's gone daft.
* TokenGoodTeammate: Elgin is a CorruptCorporateExecutive who is down with dumping gallons of toxic waste into a mine but only as long as said mine is abandoned. He draws the line at intentionally trapping innocent people in said mine and attempting to drown them in the stuff, though, and eventually angrily confronts Stevens over going too far. Unfortunately, he gets brainwashed by BOSS.
* TooDumbToLive: Oh, Bert, ''why'' did you have to stick your fingers in the toxic goo to examine it?
* WhamLine: The revelation of who "the boss" is when the Doctor finally reaches the top floor. "I am the BOSS. I am all around you. I am the computer." *[[MusicalSting Cliffhanger Noise]]*
* WhatHappenedToTheMouse: Elgin vanishes from the story after getting brainwashed. This is due to actor Tony Adams suffering an illness and needing to be taken to the emergency room. His role later in the serial was filled by SuspiciouslySimilarSubstitute James.
** The "Global Conspiracy" Mockumentary lampshades this with an older Elgin clarifying that he had appendix problems and thus, was absent from the second half of the adventure.
* UsefulNotes/{{Wales}}, boyo.
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