‘Try my size fives, Humpty.’ As usual in The Sarah Jane Adventures the pay-off involves a lot more running about than the set-up. For the CBBC audience I think that’s absolutely fair enough, but it does make it a bit more difficult to find things to talk about. Instead, my mind wanders to vague inconsistencies like why Kaagh with his high-gravity musculature can’t force open a door that the kids have just closed (or why he doesn’t just blast it open with the gun he’s just been liberally firing). There is one surprise: Lucy Skinner turns out not to be Maria’s replacement – with her warring parents and her science skills (and Clare Thomas’ CBBC acting credits), it looks like that’s the direction the show is taking.

The best things about this episode are firstly Clyde calling Kaagh ‘toad in the hole’ which is a beautiful call-back to Jingo Linx’s nickname ‘toad’. Secondly, Chrissie finally realising the truth about Maria’s adventuring just in time to play a pivotal role in defeating Kaagh with a hefty blow to the probic vent. It’s her finest hour, and Juliet Cowan rises beautifully to the occasion. I adore that although the kids make the decision to Donna Noble her, gaslighting her into thinking the Mr Smith and the Sontarans were an hallucination, the punchline is it hasn’t worked. She’s just chosen to play along, because Maria and Alan deserve a new start. It’s both a lovely character beat, and perhaps the first admission that Donna’s fate was a misstep – one, on the basis of recent location photos – RTD is still grappling with.

Next Time: The Day of the Clown