Boomtown seemed like the nil plus ultra of filler episodes

TV “Filler” is often used disparagingly to describe those episodes in television series that bridge the gap between instalments that develop an arc story or offer major character development, episodes which the general viewer should be able to skip without missing anything important or at least anything which can’t easily be explained with a couple of lines of dialogue later. The very idea of "filler" is so feared that one of the reasons Steven Moffat gave for splitting up series six was that it would mean there’d be less “filler” more event episodes.

Once upon a time, Boomtown seemed like the nil plus ultra of filler episodes, interesting for all the moral discussions over the dinner table and tourist board massaging Cardiff scenery but not of great social import, especially when the next episode was reported to be the question answering Bad Wolf (weren't we naive). Russell T Davies even revealed in Doctor Who Magazine that it was a rush job, literally filling in a gap left by a cancelled early Pompeii episode and a Paul Abbot story revealing that Rose was originally constructed by the Doctor to be his perfect companion. Or something.

Yet Boomtown is different. Boomtown has become one of the franchises most important episodes the effects of which are still being dealt with. It’s a filler episode which has retrospectively, at least in franchise terms, became an instalment that develops an arc story or offers major character development. There’s at least one of these per series, I think, though as the “arc” stories have developed, increased in density, you could argue that there aren’t any real filler episodes, that Moffat needs to be more confident in his work.

It’s the episode in which Noel Clarke has a much better idea of how Mickey should be played, bewildered and love sick, if a bit inconsistent. It is a bit rich that having refused to travel with the Doctor, he’s pretending that Rose ran off and left him, but speaking as someone who’s been there, he perfectly captures the mixed emotions of being excited for a friend who’s been enjoying exciting adventures that you’ll never have. When he steps off into the night at the close of the episodes, he’s beginning the long road to The End of Time and a Mickey seeking his own excitement.

It's an episode that for the first time directly references one of the accompanying spin-off novels. When Rose says Justicia, as well as demonstrating how its supposed to be pronounced, she's also plunging the new series directly into the canonicity debate as she's clearly remembering the events of The Monster Inside, parts of which would also later be referenced in The Sarah Jane Adventures. In one of his columns for Doctor Who Magazine, Russell T Davies suggested their were BBC charter rules against this sort of thing, but obviously there's an exception for cheap tricks.

It's an episode that for the first time were for the fisrt time the Doctor and Rose consciously notice the appearance of the words Bad Wolf. Their dismissal is delicious, but I've never quite understood why Rose needs the Welsh translating. Should the TARDIS circuits be doing that for her, and in the conventions of the series, us as well? Shouldn't every bilingual sign in Wales have the same words written twice in English, from the notice board in the station to the banner on the wall of the town hall? Rwy'n gwybod pigo, pigo, pigo ...

But it’s also the episode which led to the first series of Torchwood. Not a secret pilot by any means, the T word wouldn’t be first used until Bad Wolf (an answer during The Weakest Link), but there are still loads of parallels, not least in structure. Like plenty of Torchwood episodes, Boomtown opens with the introduction of the visiting alien (Margaret) or technology (the extrapolator) or in this case both and after an initial burst of excitement the episode becomes a slow burn investigation into the ethical consequences before the alien or technology bites back for an exciting climax.

It’s impossible to watch Boomtown now without thinking about the Torchwood base beneath the floor, of Captain Jack and co keeping shtum inside lest damage be done to the timeline. No wonder the later Jack is grumpy, seeing his tiggerish younger version and the Doctor he’s waiting for at too early a moment. I always imagine the five of them emerging to the cracked decking and explosions with Suzie, Tosh and Owen not entirely sure why their leader trapped them in the cells while the rift opened and creating a major catastrophe. With Gwen and Andy elsewhere directing traffic.

Which isn’t to say it’s a great episode by any means. Like plenty of those early Torchwood’s the final jeopardy happens because of the avarice and stupidity of the main character, in this case the rush to employ some dodgy technology to speed up a process that would work just fine with a little bit of patience, the destruction of the world nearly brought about because the TARDIS team want to shave a few hours from the charging process. At the very least, the people of Cardiff are going to have to foot the bill for the clean up, their council tax skyrocketing during a credit crunch.

The resolution is opportunistic too. As Neil from Behind The Sofa argued back in the day, it’s about as convincing as the renewal nonsense at the climax of the TV movie which as he rightly predicted was used for much the same purpose at the close of the first series. It’s a cheat so that we don’t see Margaret being led to her execution which is odd since Jackie and Mickey have already slaughtered one of her kind this series, the latter still probably trying to clean the oily entrails from his jeans. Boomtown is influential then, but not always for the right reasons.