This is surprisingly reminiscent of a Pertwee era Doctor Who (and era still a year away). It has that base under siege feel, a bunch of broadly drawn disposable characters. Steed in the role of the Doctor is the outsider. It’s so Doctor Who there’s even a disused quarry. It also is far closer to Doctor Who production values than the usual incredibly high standard of The Avengers. It has also much in common with Terry Nation’s writing for other shows, Doctor Who included. The killers, for example, are not human. They are powered by electricity, glide along the floor, and kill using an high energy weapon. The designer clearly did wasn’t inspired, as the designer of the Daleks was, though. These are small cuboids… Other Nation traits (good on high concepts, low on logic; pacey with good action, but flimsy on characterisation and witty or believable dialogue) are evident.

Plot holes? Plenty. There isn’t even an attempt to explain what made the organ play by itself. Electricity just doesn’t work like that – it makes the physics in The Positive Negative Man look sound. But credit for prophesying the Roomba: “I saw a demonstration once. A robot vacuum cleaner. It swept around the house, went back into its cupboard. Automatically plugged in and recharged itself.”

We have a horror opening (church crypt, self playing organ etc.) The caverns below are an enjoyably atmospheric setting – though like all TV caverns they have flat level floors and are exactly human height throughout. Once again Steed is brought in by a friend (this is a personal rather than a pro job).

This is a Tara-lite episode, but the scenes that she is in, mostly with an excruciatingly unappealing and unfunny sneezing professor, are inexcusably dire. When she gets to have a fight with the killer cube, it’s about as thrilling as watching a battery run flat… essentially because that’s what it is. But when Tara finally arrives at the church she does play here theme on the organ.

The Hour That Never Was bridge features once again, as all the fish in the pond below are killed (was that explained, or are we just supposed to attribute that to, y’know, “electricity”?)

Still, an episode without Mother in it is becoming a rare treat, so it’s not all bad.