‘There should’ve been another way.’ The cheeky ending mocks the campness of sombre, Saward-era Doctor Who by having Sarah Jane regret resorting to extreme measures to defeat the Blathereen while having just watched them fart themselves to death and dripping with their entrails. It’s the best moment in a script full of fun, which moves on from each element before it wears out its novelty.

So, we have Sarah Jane leaving the attic armed with a vinegar-filled water pistol for a confrontation with the Blathereen; Clyde, Rani and K9 battling a rakweed outbreak at the school, and Mr Smith defending Luke from a fatal dose of spores. In between, K9 gets his own back on Mr Smith by admitting the computer gets on his rivets, and a meaningful look from Rani to Clyde. I’m not entirely sold on the idea of defeating plants with noise, but it’s possibly a nod to The Day of the Triffids film (where the killer plants are attracted to sound). In general this is a great capstone to the best series so far.

Sarah Jane will return in The Nightmare Man

Next Time: Dreamland