There’s been a few times in Doctor Who‘s history where the show has done stories that have featured thinly-veiled features of its own fans. However, some (and I stress some, most definitely not all, not even a majority) of the reactions I’ve seen to the announcement that Jodie Whittaker is the new Doctor have crystallised an idea for me that by the far the most accurate of them – whether it’s intentional or not – was Full Circle, a story from Tom Baker’s final series.

Now, you may not be familiar with the details of this 37-year old story, so a quick recap of the pertinent points of the plot. There’s a colony Starliner from the planet Terradon that’s been marooned on the planet Alzarius for generations. The descendants of the original crew are attempting to repair it so they can take off and travel home, but Alzarius has an occasional phenomenon called Mistfall, when the rapidly-evolving Marshmen emerge from the planet’s swamps and attack the ship. The twist is revealed in the line “We cannot return to Terradon, because we have never been there.” The crew aren’t the descendants of the original Terradonians, but an earlier generation of Marshmen who took over the ship and became like them.

GARIF: We’ve got to kill them. Kill them!
DOCTOR: No. No, I think we should let them go.
GARIF: What?
DOCTOR: Look! They adapted quickly.
GARIF: They’ll learn to breath the air.
DOCTOR: Yes.
GARIF: They might break into the ship and wipe out the crew.
DOCTOR: Yes. Still the manuals in the great book room will show them how to put it all together again.
GARIF: They could learn to read?
DOCTOR: Yes. Just like they did forty thousand generations ago. They’re your ancestors.
LOGIN: Nefred’s dying words. That’s why we can’t return to Terradon.

Fifty-four years (it’s a bit shorter than ‘forty thousand generations’, but we’re in the realm of metaphor here) ago Doctor Who fandom was born, and it’s been through many Mistfalls since then. Every generation of fandom has believed it was the descendant of the original Terradonian stock, preserving that unbroken line from those who watched the opening titles of An Unearthly Child right through to the Doctor meeting himself in the Antarctic snow. And every one of them has seen their own version of the Marshmen coming to threaten fandom as we know it. Didn’t these incomers know that they were damaging fandom by having the wrong opinions about which stories were good, by writing fanzines about the show, by drawing their own art, by going to conventions, by writing their own stories, by discussing the show on the internet instead of in zines, by making videos, by posting gifsets on Tumblr instead of discussing it on forums…

Just like Doctor Who is never as good as it used to be (it’s all gone downhill since it stopped being about a policeman on his beat and started focusing on strange police boxes in junkyards…) so Doctor Who fandom is never what it was, and all these new fans coming in are just going to smash up the Starliner we spent so long repairing from when we were the young unruly interlopers from the swamps who were Doing Fandom Wrong. I’ve seen plenty of ‘I’ve been a fan since before the next Doctor was born, and she’s not just a bad choice, the fans who are cheering it on will kill the show’ from people who really should know better who don’t remember that people were criticising them for liking Peter Davison because he was far too young and blond to play the Doctor and Brian Blessed would have been so much better because he’s much more Doctorish, don’t you know?

Ian and Barbara leaving? Abandoning historical stories? Confining the Doctor to Earth? A robot dog? Three companions at once? Forty-five minute episodes? Taking it off the air? Making it in America? Making it in Wales? All these and many many more questionable decisions have killed Doctor Who, many many times over. That original idea about some scientists and their young assistant, possibly accompanied by a mysterious and crotchety old man, has become many many things over the years. The Marshmen have swarmed through the BBC as much as they have through fandom, and they’ve always rebuilt and forgotten that they were the invaders once.

The joy and accidental genius of Doctor Who is that it has no creator, no one lurking behind the scenes to tell us what it must be and what it must not be. It will die in a thousand different ways and be reborn in a thousand and one new varieties in response. None of us are the Deciders of what is and is not Proper Who, we’re all just primeval slime with ideas above its station. We can’t return to IM Foreman’s junkyard, because we have never been there. We can only move on, accept that things will change and know that there are always going to be new generations to follow us, and all of them will be told they’re going to kill what someone else loves. They’re not, they’re just passing on the wonder to those who’ll follow them for all the generations to come.