‘Don’t mention it… to anyone.’ A story that ends without a massive body count, and where the solution comes from the Doctor’s ingenious riffing on Turlough’s recollection of the Tractators’ true nature. It could do with a slightly tidier end to the Rets vs colonists sub-plot (even Cockerill shaking hands with Plantagenet would do it), and Brazen’s death seems tokenistic (and badly staged), but this is excellent: Full Circle with more sense of humour. I like it more than Bidmead’s previous stories.

It’s among Davison’s best material so far. The scenes of him being given the guided tour by the Gravis, like a visiting dignitary, are hilarious (the image of Davison and the Gravis chatting is the kind of absurd juxtaposition that this show excels at). He comes across as unflappable, witty and seat-of-his-pants brilliant. Moffat’s Doctors owe a lot to this (I can easily imagine Matt Smith performing it), as does the climax of Blink (the nature of the TARDIS turning the monsters’ powers against them). If only – if only – Davison had been presented with scripts like this in his first year, instead of Terence Dudley and Time-Flight.

Bidmead also makes the most of Turlough and Kamelion (it’s a little-known fact that the Doctor’s not lying about “Tegan” being an android – the real one is still in Little Hodcombe visiting her grandpa, and only appears in the final scene having been collected on the way to Kolkokron). Turlough popping up over the console to have a look at Gravis, and getting shoved down again, is a lovely bit of business, and there’s a sweet implication that he’s been spending some quality time with Norna while the Doctor’s transporting Gravis. It’s also Ron Jones’ best work on the show so far: some of the details are spot on – like the guard stealing food in the research room, showing the collapse of discipline in the colony. The Tractators aren’t amazing, but as a kid I crawled round the house with the washing basket on my back pretending to be one, so I can’t bring myself to be overly critical. This is my favourite Davison story so far. It’s funny that the Gravis’ plan for Frontios is the same as the Daleks’ for Earth in 2150 A.D. And speak of the devil…

Next episode: Resurrection of the Daleks