‘Who was that terrible woman?’ The Rani’s plan is perfectly consistent with her previous attempts to control the course of evolution, although it takes a hastily over-dubbed ‘it’ll overload’ to clarify why having ‘two time brains’ is a Bad Thing. This does mean the Doctor’s plan relies on making the best of a lucky break, but what do you expect in an episode that runs for five minutes?

Interestingly, UNIT have become aware of events in Walford – the arrival of Mike Yates (presumably having been drafted back) in Bessie, and then the Brigadier in a helicopter to provide backup to the sixth Doctor (a legion of fans tick that off their list) presumably means that they aren’t just flipping between bodies. Plus we have Victoria, Liz, Leela, Romana, Ace and K9 representing the full span of the show and ensuring that this is an all-inclusive celebration.

Yes, the script is very basic, the 3D camera work is distracting, and there’s none of the New Adventures references that would, apparently, have been included in The Dark Dimension. Some of the stuff going on in the background is inadvertently hilarious – like the Vervoid apparently sneaking into the Queen Vic – and it’s easy to see lots of opportunities to do something different, like a proper, Curse of Fatal Death style comedy or something less knockabout. But for better or worse, this is what we got. It set out to use the public’s affection for Doctor Who to make the world a marginally better place. Nearly 14 million people watched it, it raised £101,000 for Children in Need and did more good than practically any other story in the canon.

Next episode: Doctor Who – The Movie

Next entry: The Third Doctor and Sarah Jane