Thames television

Well as I said last week, Doctor Who tends to introduce a new companion (and even new Doctors, come to think of it) with a specific trio of episodes, and although a couple of companions (Martha and Donna) got their historical episode before they went into space, Bill follows the majority by getting her trip to the past in her third episode. And unlike the space episodes, "Thin Ice" has some generally decent ones to follow. Fortunately it's the third hit in a row in Steven Moffat and Peter Capaldi's final series.

"Thin Ice" by Sarah Dollard, directed by Bill Anderson. Spoilers after the cut.

I'm not going to say a huge amount about the episode in general - it was another good adventure, Pearl Mackie continues to feel as if she's been there forever, and Peter Capaldi finally feels like he is the Doctor, after a dreadful first year and better second one. The story's one of the better examples of the show putting forward a strong morality without feeling like it's preaching - hey, who'd have thought, after all these years maybe that "educational" remit Doctor Who was commissioned on has snuck back in.

But it was the little things in Dollard's script I really liked, the callback to the TARDIS' wardrobe being past the bins, and the reference to one of the most common remarks after "it's bigger on the inside" - not just "how is that a screwdriver?" but also "how is it sonic?," the question you hadn't even realised nobody was asking. (Although the new blue sonic screwdriver design? Pass. It reminded me of one of those pens with the different ink colours.)

As with Martha's first trip to the past we also got a reference to the fact that black people have been in the UK a lot longer than history makes out, but now with a more explicit dig at whitewashing and an overtly racist villain to boot. I also liked the fact that after last week's cliffhanger it turned out we weren't in the middle of something weird but a genuine piece of history - I'd heard of the Thames Ice Fairs - and the throwaway reference to the fact that the creature wasn't necessarily alien but could just be something not yet discovered. I don't suppose the whole series can keep up this level but this has been the most exciting start to a season of Doctor Who in years for me.