For a little woman she casts a long shadow.

In his magisterial comic book sequence The League Of Extraordinary Gentlemen Alan Moore writes a bold narrative of authentic Darwinian winnowing, allowing his advancing plot and characters to dwindle through wastage over time rather than to proliferate explosively.

At its culmination in Century: 2009 the story has very few of the original Victorian league left. Effectively only Orlando and the immortal Mina Harker remain to combat the twenty-first century antichrist, and they are forced to rely upon a literal deus ex machina in order to prevail. As things look hopelessly, lethally bleak a single new character sails down from the sky to scold the monstrous antagonist.

“I’m well famous, actually,” declaims the antichrist in the manner of a dim, self-centred, Jeremy Kyle-inflected youth. “I’m in a book of the BIBLE!”

“Tsk,” says the recently arrived stranger. “Just the one book? I’m on every page. Who did you think you were talking to?”

It’s the God-Poppins basically.

All of The League Of Extraordinary Gentlemen is brilliant, and really it works best if read from the beginning right through, but for any near-horizoned Doctor Who fans with little time to invest Century: 2009 is the one to concentrate on. Look. It has a Hartnell/Smith cameo in a couple of frames and propounds the spiffing notion that Emma Peel (now going by her maiden name) has charge of UNIT and Torchwood.

Potterheads and Bond fans will find things to delight them too.

There was a lot of Mary Poppins stuff in this year’s Doctor Who Christmas episode, The Snowmen, though wasn’t there?

Mary Poppins has always had something of Gallifrey about her. In the original P.L. Travers stories written between 1934 and 1988 she is a character of enigmatic origin who blows in without warning and leaves when the wind changes, who carries an umbrella, whose bag is smaller outside than in, and who has fantastical adventures that she then rarely discusses afterwards. If Chancellor Flavia had unbuttoned a bit and absconded in a Type 40 all those centuries ago, isn’t that what she would be like?

The two previous Steven Moffat Doctor Who seasonal episodes have merrily abstracted elements of A Christmas Carol and The Lion The Witch And The Wardrobe, and I had previously pondered what he might have planned for 2012. That the Doctor recently appeared to have removed himself from the Universe in a self-erasing huff did lead me to wonder if we were heading towards It’s A Wonderful Life territory, but no. We got a jolly holiday with Mary instead.

Poppins isn’t intrinsically Christmassy but she has, thanks to the easily-scheduled, endearing 1964 Disney film adaptation, assumed a place in the festive hierarchy.

It is clever and funny and wise of Moffat to appropriate Poppins for Whodom. It is a good fit, and gives him an opportunity once more to explore his philosophy that Doctor Who is a programme about the companions rather than about the Time Lord himself. Having said that though, the Doctor is not as drastically sidelined in The Snowmen as he was in some of the Pond episodes thank God. And, whilst there are elements of Dick Van Dyke’s Bert about his portrayal in this episode, Matt Smith’s Doctor never wanders too far from the dramatic centre of gravity.

The biggest big thing though, and there are many big things about The Snowmen, is not the Doctor, it is not the notional villain, and neither is it the ultimately revealed monster (more, joyous self-perpetuating causally-wausally stuff from King Moff). It isn’t even the hootingly funny comedy ensemble of supporting characters.

Nope. It is the loudly proclaimed inauguration of the new companion Clara that is the biggest big thing. For the second time now Clara Oswald Oswin has been introduced to us, has seduced us entirely and has then been unexpectedly killed before our eyes.

What are we to make of this?

First time round (in Asylum Of The Daleks) we didn’t find out too much about Oswin other than that, for a ship’s entertainment officer, she has a damn fine line in killing a besieging Dalek horde. If that had been the Christmas episode it would doubtless have been seen as Steven Moffat’s tribute to Home Alone. By me anyway.

Second time around, in The Snowmen, there is a clearer depiction of her ambiguous personal duality. As “Clara Oswald” she consorts chirpily with mutton-chop whiskered Cockney types (no chimney sweeps or one-man bands in evidence sadly), whereas as the more demure “Miss Montague” she is the spit-spot governess of two well-to-do kids.

The children are aware of her double life. They get her to use her “secret voice”, and beseech her to tell them more of her stories. Given that we know the one about the man who lives on a cloud is true should we make the same inference about her Big Ben story? Or the one about inventing fish? You wouldn’t put it past her now would you?

What the actual heck is going on with Clara?

The internet is not short of speculations, ideas and frothy-minded thinks, and many of them are, in fairness, quite persuasive. This galloping, ravening urge to know things in advance though is just the fannish equivalent of shaking and squeezing your presents whilst they are still under the tree. When you reach a certain age you lose that impatience I have found, and it is easier to just enjoy what is in front of you.

I don’t think the Mary Poppins stuff is actually that significant. Steven Moffat is the emperor magpie and takes what he needs from wherever it is. There is the taller-on-the-inside clever staircase, the umbrella, the flying, the kids and so on to give us a handle on Clara, but that is all it is. An efficient contextualising device.

And there are plenty of homages in The Snowmen that have nothing to do with Poppins: There are cheery plunderings from Citizen Kane (a lonely, old snowglobe-owning, rich man never frees himself from the influence of childhood); Les Diaboliques (there’s a body in the pool, or is there?); and even Chandler once again (as Vastra’s interview with Clara echoes Philip Marlowe’s introduction to General Sternwood at the beginning of The Big Sleep).

None of it, I think, signifies anything other than Moffat’s ingenious ability to suggest an atmosphere from a few quick semiotic flourishes. It’s not deep but it is clever.

I like Steven Moffat a lot. In his tenure on Doctor Who he has done very little to pander to the demands of fans (new and old) and, though this seems to have brought him a large amount of personal derision, it has been of immeasurable benefit to the programme.

When he has overseen the return of old enemies (the Autons, the Silurians, the sort of Nimon) he has done it respectfully but imaginatively. Same with the Great Intelligence here in The Snowmen. He does, however, seem to understand quite sensibly that for a programme to thrive for fifty years it is not enough to dwell on past favourites, it has to be constantly innovating. So in Moff’s time alone we have had the introduction of the Dream Lord, Liz Ten, Van Gogh, Churchill, Nixon, Canton Everett Delaware III, the Silence, Prisoner Zero, the Flesh, the Pandorica Alliance and loads more, all of which can be revisited at will any time in the future.

One of the more insistently shrill, fannish exhortations is for there to be some sort of New Who/New Sherlock crossover. Now, ignoring the fact that there has already been the ne plus ultra of Wholock convergence in Robert Holmes’s sublime The Talons Of Weng-Chiang (1977), this is still the stupidest of ideas. You know how good the Alien Versus Predator films aren’t? Well this would be that, but worse.

Impudently Moff has acknowledged the unfeasibility of the idea in The Snowmen whilst, at the same time, executing it. After a pleasing implication that Vastra and Jenny are the progenitors of Conan Doyle’s stories in The Strand magazine Moffat then dresses the Doctor up in the dimmest popular conception of a Sherlock Holmes outfit and has him do a crass deductive pantomime: “Do you have a goldfish called Colin?” “No.” “I thought not!”

I have found it funny each time I’ve seen it, and am delighted that now, at each subsequent Wholock demand, we are allowed to say, “You’ve already had it. There it is in The Snowmen.”

In fact for what could have been a thoroughly grief-drenched affair The Snowmen is pleasingly rich in laughs, and mostly these come from the Blackadder/Baldrick dynamic of The Doctor and Strax. “I’m the clever one. You’re the potato one.” Smith’s comic abilities have never been in doubt, but Dan Starkey’s performance as Strax is a magnificent revelation. Still, I think that sometimes less is more and I am emphatically not one of those clamouring for a thirteen-episode Vastra/Jenny/Strax spin-off. I deeply enjoyed what we got though.

Did I miss the explanation of which of the Doctor’s friends brought Strax back to life, or has that been left intentionally vague? Also I am not quite clear on which not-red-wine drink Vastra was enjoying. Vimto, hopefully.

The rest of the humour derives from Jenna-Louise Coleman’s boisterous, glittering performance as Clara. I haven’t dwelt too much on J-LC because there’s a limit to how much thigh-rubbing, Cosmo Smallpiece mimicking you need from me. Presumably.

Still, though. What a little teapot, eh?

You also don’t need me to tell you how superbly lugubrious Richard E. Grant is as Simeon, or how wonderful Tom Ward is as the lovelorn, Von Trapp-esque Captain Latimer. As chaos unfolds about the latter gentleman, still the only question he can think of to ask is the poignantly rhetorical “You have a gentleman friend?” to Clara. So sweet.

The whole thing looks lush too in the way-more-than-safe pair of hands that is Saul Metzstein. This is some of the most sumptuous TV drama around.

It is a relief to me that ratings and audience satisfaction have been high. I had slight concerns that the subject matter might be a bit savage or a bit opaque for kids, and that the continuity-dependence might have been alienating for the non-nerdish adults.

Once again we seem to have got away with it though. This year we had Christmas Day teatime telly that contained carnivorous telepathic snow, a Silurian detective, a Sontaran valet and a baffling governess who seems to exist across time and space. What did EastEnders have, by contrast? I don’t know. I didn’t watch it. But I am going to guess at adultery and fistfights.

We won.