After The Seeds of Death, it’s another story that’s concerned with the realities of space travel: this time, the vast distances, and long journey times between locations – mostly through an empty void. While that makes this episode a bit plodding, it also helps to set the scene quite well so that the end of the episode – with help at least 90 minutes away, and no way back to the TARDIS – we feel the isolation of the Doctor, Jamie and Zoe. It’s creepier and more hopeless than any number of cliffhangers where a monster threatens to shoot them, because this time it’s physics they’re up against.

There are lots of quite impressive things about the episode. The model work looks top notch – the methodical, steady motion of the spaceships reflects the reality that viewers must have been familiar with from the contemporary Apollo missions. And the models themselves look good: the Beta Dart like a mosquito; the V-Ships more muscular, flying over the camera like prototype Star Destroyers.

Robert Holmes’ second script also contains more of the seeds of his later successes. The offhand references to the Interstellar Space Corps being caught up in brush fire wars, and lines like ‘Another gift from the home planet’s taxpayers’ ground the sci-fi in something recognisable while sketching a wider world beyond the edges of the story – the same trick Holmes later pulls in things like The Caves of Androzani. His space pirates are also recognisable “types” with Caven the career criminal and Dervish his ex-government accomplice, more fearful of his old colleagues.

But it’s not all good: the ISC crew are a bit less convincing than the pirates, partly due to Donald Gee’s odd American (?) accent, but mostly because of Jack May’s bizarre fruity performance as General Hermack who seems less like a weary, highly-decorated space veteran and more like a provincial rep mainstay holding court in the theatre bar. Interestingly, he’s the second Henry VI in as many serials (after Terry Scully), but his performance here has nothing of the ethereal uncertainty of the mad king.

Nicholas Bullen’s costumes are also very weird indeed: instead of the jumpsuits of the last few stories, he goes all out Blake’s 7 several years early, with space armour for the pirates, billowy sleeves and bling for the ISC crew, and the most absurd flouncy shirt with massive lapels for Jamie, who looks like he’s stopped off en route to Eurovision ’69. They definitely look like they’re boldly going where no omi has gone before.

Next episode: “The Space Pirates” – Episode Two