‘Complete and utter, wonderful nonsense. How very, very silly.’ By the time this aired, David Tennant had made his bombshell announcement that he’d be relinquishing his Doctorate before they had to wheel him out of the TARDIS in a bath chair. As such, this arrived amid febrile speculation on who could possibly replace him. The episode title absolutely plays into this, as did a lot of the publicity which included interviews with David Morrissey demurring when pressed on whether he really was the next Doctor. In that context, this is possible the most on-point Doctor Who episode ever.

The first half of this remains probably my favourite Christmas Day material. It helps that it takes place in Victorian Christmas Card scenes, with gorgeous images of the Doctor wandering round a Victorian market, or Miss Hartigan, in crimson, striding through a snow-white graveyard. It all looks properly wintry and chilly, unlike some of the previous Christmas episodes.

I’m also a great fan of the Doctor’s relationship with Jackson Lake. Their first encounter – which was released early as a tease – is brilliant. Lake establishes his Doctorish credentials economically but emphatically, referencing the sonic screwdriver, the TARDIS and the Time Lords. He also has a companion, Rosita, whose name combines Rose and Martha, and whose attitude is pure Donna. Her account of her first meeting with the Doctor/Jackson is very reminiscent of Rose’s opening narration in Army of Ghosts.

RTD’s script keeps the audience guessing, with Jackson’s fob watch and potential post-regeneration amnesia providing possible clues to fans, as the Doctor gradually probes his memories and he starts to recollect the fateful night he regenerated during a battle with the Cybermen. It’s not until Jackson’s TARDIS is unveiled that most of the audience would have cottoned on that Jackson’s not who he thinks he is.

These are some of the best scenes in the piece, as Tennant steps back to let Morrissey take the lead, performing Lake’s loss, confusion, and grief in a brilliantly compelling way. The compassion and tenderness Tennant projects as he promises to help Jackson, ‘we’ll find out, you and me together’, is rather beautiful, as is the moment he claims to be Jackson’s companion. We’ve haven’t really had a Doctor/companion buddy relationship since the 1960s, so this is refreshing.

Then, the reveal happens with the first JNT style clips compilation we’ve got in the new series (sadly, there’s no cutaway between the images of McGann and Eccleston that would let the Hurt Doctor slip in). This was a lovely moment – up until 2008 some people could still claim “McGann doesn’t count” with a straight face, but there he is, the Doctor as much as any of them. Sadly, this happens 30 minutes through the episode, with another half hour to go. And this is where I think things start to go a bit wrong.

Ideally, I reckon, this reveal should lead into the final act. Instead, the back end of the episode has a section of Jackson rescuing Frederic from Miss Hartigan’s workhouse, where children have been press-ganged to construct a CyberKing. This makes sense, and I suppose there’s a theme of two-faced Victoriana with Jackson on the one hand and the hypocritical eminences on the other.

But it then pivots into a giant, stop-motion style CyberKing stomping over London as Miss Hartigan plans to take over the world until the Doctor convinces her to change her mind – a first, given she has already told him, ‘No one’s ever been able to change my mind.’ Again, there’s a theme of changing minds – Jackson, again, and the Doctor at the end (‘Just this once, you’ve actually gone and changed my mind’), but what the point of any of this is is harder to fathom. Don’t be too rigid in your thinking or you’re no better than a Cyberman, perhaps?

I suppose existential pondering isn’t what anyone wants after a big Christmas dinner, and I think The Next Doctor is fun enough as Christmas Night entertainment. But, like Christmas Day itself, it all goes to pot after the excitement of the first half becomes bloated and sleepily postprandial in the second. What’s left is wonderful nonsense, but for a moment it looked like it was going to be more than that.

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