‘I’m warning you, last time that man turned up it was a disaster.’ Views differ on whether the predictability of Noughties series structures was a good or bad thing. Either way, by 2008 we knew what to expect from the first two-parter of the season: a big, Earth-based story with a returning monster. After Cybermen and Daleks, it’s the turn of the third of the Big Four monsters – the Sontarans. At the time, the redesign was greeted with diminishing enthusiasm after the near-universally praised Daleks and the look-good-but-too-stompy Cybermen. Personally, I think the prosthetics are great, and the main complaint about the armour – it’s blue – is true, but barely matters.

Most importantly, Helen Raynor takes her inspiration almost entirely from Robert Holmes and Kevin Lindsay. These Sontarans sound like they’ve come straight out of Sandhurst, filtering everything through the lens of military strategy, and with dry wit. Christopher Ryan is perfectly cast as Staal, becoming the worthiest Sontaran since Styre, and Dan Starkey takes a similar approach in the less prominent role of Skorr (though he does get the lovely call-back about the female ‘thorax’). The result is exactly what Holmes wrote in The Time Warrior: monsters with their own style and tonnes more character than usual. Their backstory (a clone race which produces battalions on demand) provides the source for the B-plot of a copy of Martha being produced to infiltrate UNIT. Basically, this feels like a story built for its villains.

Well, mostly. The ATMOS angle and boy genius Luke Rattigan (so similar to Adam you wonder why they didn’t get Bruno Langley back) could fit with practically any invaders, although there’s a token attempt to talk about how 800 million cars can be converted into weapons of war for the Sontarans. It feels like after fat pills, Christmas decorations and earpods the writers’ room was casting about for another common-or-garden object to turn into a device of death. And for the third Earth story in succession we get an investigative journalist unmasked (Nakashima following Vivien Rook and Penny Carter). The killer cars work fine but are the most unremarkable part of the story.

Elsewhere, there are loads of great moments for the regulars: Martha meeting and bonding with Donna; the Doctor having to resume his UNIT role; Martha and the Doctor sharing a tense moment as he gently criticises her working in the military; Donna returning home to Wilf and Sylvia. Tennant’s performance in Rattigan’s office, as he goads Staal about the Sontarans’ weakness while finding a squash racquet and ball to exploit it is brilliant. The joke of Donna getting a leaving scene where the Doctor commends her brilliance takes on extra weight once you realise it’s there because she can’t have one at season’s end.

Next Time: The Poison Sky