Doctor Who Regenerations: A Tribute To 11 Epic Changes

4. March 1981: Fourth/Fifth Doctor

Logopolis is a reasonably complex plot overlayed on a fairly basic premise: the Doctor wants to get the TARDIS' Chameleon Circuit repaired. To do so he needs to measure every single dimension of a Police Box on earth, then take the measurements to the planet Logopolis. The Logopolitans are insanely clever mathematicians who, amongst other specialist skills, can convert the Doctor's measurements to "a precise mathematical model" and overlay them on the TARDIS - et voila! - somehow, the TARDIS will have a fully operational Chameleon Circuit again and no longer be stuck in the shape of a Police Box... or something like that. The relatively involved story culminates in the last ten minutes of episode four with The Master and The Doctor holed up high above the ground in the control room of a huge satellite dish, attempting to establish data connectivity with deep space in order to stop the universe from collapsing in on itself. The Doctor is a reluctant party to the collaboration with his arch-nemesis and with good reason; The Master's agenda is as self-serving and warped as ever. Once the interstellar connection is established The Master broadcasts his message of domination to the universe via the giant satellite dish using, of all things, a Dictaphone recording. But having spent most of the episode setting up the interstellar connection to save the universe, the Master's sole trump card is that he could easily generate a recursive pulse that would close the connection forever. To avoid complete annihilation, the Doctor hacks into the cable along which the connection was established, severing both it and the connection forever. Not entirely clear on how that was any better or worse than The Master sending a recursive pulse, but presumably The Doctor felt the outcome would be somewhat better than the aforementioned annihilation. After some more fun and games with The Master, The Doctor falls from the gantry of the giant structure, with only the severed cable preventing him from plummeting a hundred feet to the ground. As he dangles mid-air, suspended from the end of the cable, The Doctor sees visions of some of the more fearsome foes from his seven year reign, before losing his grip first on the cable and then on the framework supporting the structure and plunging to his predestined demise. His growing collection of pre-twenty-something companions watch all of this from a distance, then race across to the base of the structure to find The Doctor in a crumpled heap on the ground. As they call out to him, images of his former companions also call out to him. The Doctor tells Adric, "It's the end, but the moment has been prepared for", before waving his arm in the general direction of the dodgy green-screen effect behind him. The Watcher "was The Doctor all the time", Nyssa explains as the mysterious, featureless being merges with The Doctor's body. The Fourth Doctor's features disappear beneath a cocoon-like outer layer, which then fades to reveal a new, younger man beneath the colour-coordinated burgundy coat and oversized scarf combo. More so than any previous classic series regeneration, it's a powerful moment and the emotion of it is almost unexpected. Tom Baker had been in the role longer than any other actor. He'd made the role his own and became the quintessential Doctor in the process. But from that moment, Tom Baker's iconic Fourth Doctor was no more.