A good half of this episode focuses on Jamie and Kemel’s journey fighting their way through Maxtible’s house, avoiding traps. This includes a five-minute wrestling sequence set to some stirring Dudley Simpson music, which looks and sounds like something from Star Trek. The liberal presence of axes, ropes and other dungeon paraphernalia adds to the Kirk-in-an-arena feel.

Indeed, the fact that the Doctor and the Daleks are watching this on monitors to learn about the Human Factor (which the Doctor summarises as courage, mercy, instinct and self-preservation) feels very much like the kind of thing Star Trek aliens did all the time. However, the likelihood of Whitaker having actually been influenced by the show, which debuted in September 1966, seems low, and it’s more likely they were both drawing inspiration from earlier sources like Flash Gordon.

These scenes also prove that Jamie can read – Kemel’s name written in the dust, and Victoria’s initials on a carefully-planted handkerchief. Which slightly ruins that Companion Chronicle that has Victoria teaching Jamie to read (although knowing Jamie he’d play dumb just to get Victoria to sit with him),.

With Troughton taking his first week off in the seven months since he started, the Doctor’s participation is limited to a few short film inserts. Instead, the focus finally turns to Maxtible, always a shadier character than Waterfield, and embodying the worst elements of the Human Factor – duplicity, self-righteousness and greed. He plans to kill Waterfield to prevent him from talking, and offers himself up as a willing collaborator to the Daleks – even though he’s pushed to the floor for his presumption. He’s even willing to sell out his own daughter and her future husband all for the promise of the secret of alchemy, turning lead into gold.

There’s probably a long thesis about Whitaker’s alchemical interests but the key point seems to be a Biblical one: that lust for knowledge has been the downfall of humankind from the very beginning, and the secret of this forbidden knowledge is being offered by the Daleks, which makes them the metaphorical Serpent. And as an embodiment of the first evil, the Dalek pottering about with a lace hanky is very funny.

Next episode: The Evil of the Daleks – Episode 5