Every child loves snow. The urge to build a snowman is almost primal. But, as the opening shot forewarns – a snowflake snaps its “jaws” high in Earth’s atmosphere – this is the Christmas story where snow turns nasty. Time to shiver!

This year’s Doctor Who special couldn’t be better timed – what with Raymond’s Briggs’s The Snowman and The Snowdog debuting on Channel 4 and adorning the RT Christmas cover.

The Snowmen, Steven Moffat’s more macabre yuletide offering, opens in England, 1842. A lonely boy called Walter makes a snowman, which he talks to – and it talks back to him… So far, so creepy. The action leaps ahead 50 years and freaky snowmen are sprouting up all over the place, emitting a “low-level telepathic field” and baring icicle fangs. But what threat do these creatures pose exactly..?

There’s not much more I’m prepared – or permitted – to reveal about the story. On 30 November I went up to BBC Television Centre (it’s reassuring to know TVC still has its uses) with my RT colleague, TV editor Alison Graham, and a posse of other TV journalists to watch a rough-cut preview of The Snowmen. We were warned that the music and fx weren’t quite final – and there are four specific aspects of the drama we’ve been asked not to mention.  

What I can tell you is that there’s a striking new Tardis control room (get a first glimpse here). We have a proper introduction to Matt Smith’s new co-star Jenna-Louise Coleman, who is dazzling and perky as Clara, and not as cocky as her looky-likey Oswin in Asylum of the Daleks.

Richard E Grant guest-stars as chilly Victorian misanthrope Dr Simeon. Tom Ward plays kindly but uptight widower Captain Latimer, living at spooky Darkover House with his two children (played by real-life siblings Ellie and Joseph Darcey-Alden). The biggest coup, though, is getting Ian McKellen to provide the voice of the snowmen. (I must confess that at the preview I first identified the voice as Patrick Stewart’s; don’t ask me why, but I often get their actorly timbres muddled.)

Matt Smith is, as ever, just wonderful as the Doctor. For me, he hits every note, every time. Impeccable. In this story, the Time Lord is reclusive, retired, still stung by the loss of the Ponds. And he looks fabulous in his Victorian costume, reminiscent of several earlier Doctors but, in silhouette, closest to Troughton.

As you’ll know from Children in Need, the Doctor’s chums from A Good Man Goes to War are returning: Strax the friendly Sontaran, as well as Vastra the Silurian/dominatrix/sleuth and her cockney “maid” Jenny. These two were a huge hit first time around and here, happily, it’s made crystal-clear that they’re partners in the most modern sense.

We also have “living” snow, a new setting for the sonic screwdriver, a heavenly spiral staircase, and a peculiar critter that looks like a refugee from the Jon Pertwee era. What Moffat cleverly gives, though, isn’t so much a nod to the past, but nods to the future…

So don your scarf and mittens at 5.15pm on Christmas Day, BBC1, and shiver…