‘If something can be remembered, it can come back.’ On one level, this out-does most of RTD’s series finales, with a long pre-titles sequence that includes extra scenes of Vincent, Churchill and Liz 10, and gifts River her all-important vortex manipulator all in the service of getting the Doctor and Amy to Britain in 102 AD. It tops this with an episode including not only the Daleks and Cybermen, but Sontarans, Autons, Judoon and Sycorax, and a cliffhanger featuring the death of Amy and the end of the universe.

On another level, it’s about the power of stories: the Pandorica, the Romans in Britain, even Rory are all constructed from Amy’s childhood stories, and the Pandorica itself has become the stuff of legend. So too has the Doctor: ‘I hate good wizards in fairy tales. They always turn out to be him.’ Even ‘structures can hold memories, that’s why houses have ghosts.’ The point being, you don’t forget a good story, and if you can remember it, you can retell it – an idea that signposts the resolution.

And then, it’s a horror story: the Cyberman in the Underhenge isn’t just a stomping robot person, but a walking conversion version factory stuffed with the decayed remains of its previous victim and hungry for Amy’s flesh. River’s journey to Amy’s house, as creepy as ever, empty and ominous. The sinister voice croaking, ‘Silence will fall.’

All of it is, to an extent, elaborate misdirection: there is nothing inside the Pandorica, the thing that would, ‘just drop out of the sky and tear down your world’ is going to be the Doctor. From the Daleks’ point of view, you probably would describe him as ‘a nameless, terrible thing, soaked in the blood of a billion galaxies’, although given the Pandorica’s reputation is presumably an invention to draw the Doctor into the trap, you have to imagine their agents going round spreading the story; Cybermen sidling up to travellers in some space cantina whispering, ‘Psst, have you heard about this Pandorica?’.

I think it’s enormous fun, although I have my reservations. The Doctor’s Stonehenge speech it’s essentially a moment of desperate self-mythologising, the Doctor turning himself into a story so it sort of fits the theme. Rory’s return is slightly more problematic: I can sort of buy Amy having residual memories of him (hence her crying when she sees their engagement ring) as it’s not entirely clear how there can be a photo of him when he never existed. Presumably the cracks just wipe people’s memories of events rather than the events themselves – hence duck ponds with no ducks.

But putting these aside, it’s an incredible achievement, cleverly tying together the preceding series, and raising the stakes for the climax.

Next Time: The Big Bang