“The heart of the machine is under the column”
The Edge of Destruction (1964), written by David Whitaker
In this First Doctor story, set almost entirely inside the TARDIS, a series of strange events makes everyone tense and agitated. Come the finale, as the Doctor announces they’re on the brink of destruction, Barbara realises something. The ship, the TARDIS itself, has been giving them clues. That’s what the strange events have been.
The Doctor, interestingly, insists that the TARDIS cannot think, but states that its power source is beneath the central column on the console. The idea of the TARDIS being sentient, and the importance of its power source beneath the console, are developed further in the post-2005 series (especially Neil Gaiman’s ‘The Doctor’s Wife’) and becomes a crucial plot point at the end of series one (in both ‘Boom Town’ and ‘The Parting of the Ways’).
“No, they have been recognised on Planet 14”
The Invasion (1968), written by Derrick Sherwin
Tobias Vaughn, head of an electronics company, is helping the Cybermen invade Earth. Talking to a Cyber-Planner (a computer-brain with a gift for strategy), they look at security photos of the Second Doctor and Jamie. The Planner recognises them from “Planet 14”, which makes Vaughn question how they could have been on another planet.
Viewers with good memories might have been watching this in 1968 and thinking ‘Hang on…when were they on Planet 14?’, because this was the first anyone had heard of it. Given the Doctor and Jamie had met the Cybermen onscreen three times at this point, the fact that Derrick Sherwin gave them another encounter has led writers to try to fill in the gaps, notably Grant Morrison in their 1987 comic strip ‘The World Shapers’ and Steven Moffat in ‘The Doctor Falls’, where he suggests parallel evolution of different Cybermen, making them adherents of a repeated meme.
