‘Hello, dear. I don’t understand any of this.’ The bulk of this episode is the first substantial appearance of the Sontarans as villains since 2008. I sense an effort to rehabilitate them as credible baddies after years of Strax’s antics. But wisely, Chibnall doesn’t try to make them entirely serious – they are, after all, Robert Holmes creations with all the cynicism that implies. Extrapolating from classic series appearances, when they frequently seemed closer to cracking the secrets of Gallifrey than even the Daleks, these Sontarans have launched a temporal (not ‘tempura’, Dan) offensive, enforcing Jingo Linx’s claim to the Earth from their base in present-day Liverpool.

I think this plot works well. The Sontaran grasp of military strategy and their love for the glory of war comes across strongly – probably more strongly than in The Sontaran Stratagem. Their vulnerabilities – bashed on the probic vent with a wok – provide some comic relief, and their new-old look is great. The use of some cinematic, sweeping camera work, revealing the battlefields of Crimea and the shipyards of Liverpool, give this a great sense of scale. If the solution is a bit timey-wimey, at least the Doctor also got so show some ingenuity in dealing with one of the incursions without resorting to a ‘temporal implosion’.

I’m less sold on events in the Temple of Atropos on the planet Time, and the overarching plot of Flux. Some of the dialogue sounds like Chibnall’s fondly remembering Sapphire and Steel – ‘Time is destruction… Time must not be unleashed… Time is evil, and it will seek its own.’ What this amounts to in practice is Yaz and Vinder standing around a room while Swarm and Azure mince in and blether on. It gives some sense of the bigger scale of the threat to the Doctor, but oblique, ethereal menaces are a tough sell (the Time Lord scenes in The End of Time are a good example of how to do this kind of thing right), and by the second time Azure dissolves one of the lampshade priests instead of cutting to the chase I was starting to get irritable – especially when the Doctor’s already had a dreamy black and white vision of a floating house. It’s all very Terminus.

Fortunately, though, the focus is on the rather more tangible Sontaran invasion, and the Doctor’s attempts to end the war with as little bloodshed as possible. Mary Seacole gets slight role but it’s better than the inspiring women of Series 12, as though Chibnall’s been paying attention to the criticism and knows that just dropping them into a story isn’t enough. Dan’s parents turning up to info (and wok) dump is possibly a step too far, but I loved Karvanista arriving in the nick of time, and his emerging buddy relationship with Dan. So, on balance, this is a stronger episode than most of the previous series’, and an improvement over the opener.

Next Time: Flux Chapter Three – Once, Upon Time