The main point of this episode is to highlight the differences between the Drahvins and the Rills. The Doctor and Steven think that the Drahvin spaceship is old fashioned, and the Drahvins aren’t very intelligent (an impression reinforced by the particularly gullible Drahvin guarding Steven later in the episode). The Doctor also points out that the metal of the Drahvin spacecraft is ‘Very common… Old trash’.

In contrast, when he and Vicki discover the Rill base they find it surrounded by advanced-looking encampments and repair shops, with the implication that while the Drahvins haven’t tried to help themselves, the Rills are doing their best to effect the necessary repairs to escape the doomed planet. And while his screwdriver could scratch the metal of the Drahvin ship, it doesn’t make a mark on the ‘far superior’ Rill vessel. The design work neatly reinforces these differences. The Drahvin spaceship is cramped, dark and drab. The Rills’ is airy, light and packed with advanced-looking equipment.

Beyond this compare and contrast, the episode is a bit sparse. Having established that the Drahvin drones are an artificially created and rather stupid bunch, there’s nothing much to do with the idea except to repeat it, to the obvious exasperation of Maaga – who’s attempts to convince Steven to take her away again give Stephanie Bidmead the best material of the episode, and allow Peter Purves a bit of space to shine away from Hartnell and O’Brien. Steven comes across as egalitarian (questioning why only Maaga should get the good food and working gun), shrewd and insouciant. He also has a nice line in banter with the Doctor, as they gently squabble outside the Drahvin ship.

Having taken some time to establish that the Drahvins and the Rills are quite different, the episode finally introduces the Rills right at the end, as one peers out of its ship at Vicki and the Doctor. It’s a reasonably effective end, and probably the right midpoint for the story, but there’s a sense that there just hasn’t been enough material to justify taking 50 minutes to get here. Perhaps it’s end of production block blues, but there hasn’t yet been an episode quite this lacking in incident.

Next episode: Air Lock

Trap of Steel no longer exists. Not in any of its regenerations. This review is courtesy of the excellent Loose Cannon reconstruction