Initially, the episode continues to dangle the possibility that Waterfield might be a rival member of the Doctor’s people. Jamie wonders whether he might have invented a time machine like the TARDIS – which the Doctor dismisses as unlikely, even though Jamie’s almost spot on. And Waterfield’s angry confrontation with the Dalek that kills Kennedy makes him appear even more Doctorish. When he wakes up from the knock-out gas in Maxtible’s house, the Doctor is clearly disturbed to learn that he’s been captured by the Master, which is a lovely opportunity for a ret-con.

The episode begins with some flashy Derek Martinus direction, as a Dalek appears over Kennedy’s shoulder as he robs Waterfield’s safe. It’s followed by a nicely creepy scene of ticking clocks in the dark antique shop, as the Doctor and Jamie arrive for their appointment with Waterfield. Shortly afterwards, there’s a wipe from the Doctor’s face to a photograph of him. And the transition from 1966 to 1866 is excellently established, with typically detailed BBC set and costume design, some gentle piano music and an over-familiar housemaid setting the scene even before Maxtible arrives to confirm the date.

Best of all, the single scene between the Doctor and the Daleks is brilliantly set up. Maxtible’s talk of becoming ‘victims of a higher power’ and ‘creatures bursting through’ as he and Waterfield tested their theories, and Waterfield’s distraught cry of ‘the horrors of time travel’ position the Daleks as some sort of Lovecraftian cosmic terror, unleashed by human beings delving too deeply and too greedily into the higher mysteries. The Doctor’s bark of ‘Static?!’ when Maxtible describes the nature of their experiments means that when a sole Dalek bursts from the time cabinet, he greets it with resignation.

Living up to the story title, the Daleks really do seem to be at their most evil. Our first introduction to Victoria is seeing her distress as a Dalek threatens her with force feeding. And Maxtible’s description of their plan – to discover the essence of humanity and transplant it into their alien nature – feels like an assault on the nature of humankind.

This is all fairly dark, but Troughton and Hines continue to develop their excellent double act – for example, when Jamie knocks over a vase in Waterfield’s shop immediately after the Doctor warns him not to. Even this, though, makes the conclusion of the episode even grimmer: the Doctor will have to test Jamie to isolate the Human Factor. Maybe while he’s at it he can also work out when Jamie learned to read in between the second episode of The Faceless Ones, when he couldn’t even hold a paper the right way up, and now, when he can quickly read the date on a receipt.

Next episode: The Evil of the Daleks – Episode 3