From the depths of the ocean to the surface of the Moon: the TARDIS has arrived 101 years after the First Men. Given the backdrop of the space race, this feels as contemporary 1960s as The War Machines, and the iconography here is almost consciously quintessential: the Moon, a flying saucer, a base under siege and, at the cliffhanger, the first appearance of the familiar, silver-suited Cybermen.

The second Doctor’s characterisation has also settled: Troughton has evidently worked out how he wants to play the part. For the first time, he’s oddly cautious about leaving the safety of the TARDIS: there’s none of the delighted anticipation of prehistoric monsters from The Underwater Menace; none of the reckless eccentricity of The Highlanders or The Power of the Daleks. The script is unclear whether this is because of the bumpy landing, a sensation of something evil, or just the knowledge of all the things that can go wrong in an airless environment. This sounds an altogether more subdued, precisely detailed performance.

The episode plays out very similarly to Pedler’s The Tenth Planet: rather than wrapping up in warm clothes, the Doctor directs his companions to find spacesuits (for the first time since the arrival on Vortis). They’re quickly brought into another isolated base, peopled by an international crew and led by a gruff commanding officer. And International Space Control even makes a comeback. However, some of the obvious flaws in the earlier story (mainly Pedler’s complete failure to give the Doctor and Polly any active role, and a lack of mystery) are improved on. The Doctor and Polly volunteer to go and help in the sickbay, ministering to the victims of the mysterious plague (and keeping an eye on the unconscious Jamie), while Ben gets to snoop around the Moonbase and its impressive central set.

And as only the second returning monsters, the build-up to the reveal of the Cybermen is very well handled (even the title doesn’t immediately give away that they are back) – looming shadows, glimpses of an arm, a hand shooting electricity – until the climax.

I’m torn on the new Cyberman costumes. They’re definitely more credible, streamlined armour for a race of planet-conquering robot people, but they lack the eerie otherness of the Mondassian Cybermen. Maybe these are the equivalent of Cybermen soldiers – quickly converted, more mechanised and hard-wearing than the true Mondassians, who have preserved as much of their original bodies as possible, inside the life support suits? I’m sure there’s a Missing Adventure somewhere that explains it all.

Next episode: The Moonbase – Episode 2