Frontier in Space/Planet of the Daleks was inspired by memories of the 12-part Daleks’ Master Plan, but separating the planet hopping/interstellar politics/enemy Time Lord elements of that serial from the Dalek city on Kembel. Terry Nation’s first script for the programme since 1966 picks up almost precisely where he left off, with a desperate mission to a Dalek-infested jungle planet populated by deadly flora that can turn a human being into a vegetable. Instead of Agent Bret Vyon we get Taron the Thal, but for the most part this repurposes Mission to the Unknown and the first five episodes of The Daleks’ Master Plan. It even has a desperate message recorded on a cassette.

That’s not really a bad thing. No-one had seen the Daleks do anything like this for seven years, and the 10th anniversary season has an excuse to revisit the old classics and do them in colour (The Avengers got away with re-making B&W episodes in colour across a much shorter timescale, and Mission: Impossible was doing basically the same three scripts in rotation). After hastily inserting them into Day of the Daleks (and coping with three props) the production’s stumped up for another seven Daleks and rented a movie prop to give them more presence, and the show hadn’t done an alien jungle since Season Three so it feels worthwhile having another go (and judging by how often jungles will pop up across the remainder of the 1970s it seems Spiridon was a success). In short, there’s nothing hugely innovative about this, but it’s not pitching for innovative, it’s pitching for quintessential: the ultimate Dalek space story. So far, it mostly gets away with it, with the return of the Thals and the mention of Ian, Barbara and Susan (in a reminiscence that otherwise fits Genesis of the Daleks much better) acting as a sweet kiss to the past for anyone old enough to remember when this kind of story was the show’s bread and butter.

Mostly it gets away with it, but there are some bits that suggest Terry Nation hasn’t seen the show since he last wrote it. After a sustained run of character development, Jo is back to being a hapless damsel in distress, and the idea that the Doctor could run out of air in an infinitely large space full of air is beyond ridiculous. Pertwee and Manning sell it, obviously, but this is a lot thinner material than they’ve been getting recently. Bernard Horsfall is also making the most of an underwritten role, playing Taron with watchful, wits’ end energy, and helping to land the idea that these Thals are desperate survivors. And they have something to be scared of: the cliffhanger is not that there are Daleks on Spiridon – it’s that there are invisible Daleks on Spiridon. A deadly jungle full of invisible Daleks…

Next episode: Planet of the Daleks – Episode Two