‘Everybody does what they were always going to have to do from the very beginning. Sit down and talk!’ Cold Blood with Zygons. On the surface this looks and sounds profound, with the Doctor giving impassioned speeches about war and dead children, and the importance of forgiveness (I could really have done without the Hughie Green impression, but I can let that slide. I’m more dubious about whether it’s actually in the Doctor’s gift to forgive Bonnie rather than, say, the families of the aircraft crew she killed or the people her followers have slaughtered). It’s all very punch the air stuff, until you think about it for more than half a minute and realise that it entirely hinges on the Zygonists having no ideology and no aims, Bonnie realising what a silly girl she’s been and the Zygons all going back to their quiet, hidden lives.

For a Doctor Who ending, that’s a bit crap. Even the Silurians were going to get a better deal, to practice their own cultural beliefs in the parts of the world humans couldn’t easily inhabit. But Bonnie, who five minutes before was on the full Daenerys Targaryen “I know what is good” kick (‘we will die in the fire, instead of living in chains’), meekly surrenders in the face of the Doctor’s finger-wagging. Still, no harm done, least said soonest mended and let’s just forget about all the murders.

The bigger problem is, The Zygon Invasion set Bonnie up as the al-Baghdadi of Zygon ISIS, reaching for a parable I was gravely doubtful the series had in itself to pull off. The weakness of suggesting an ideologically-motivated zealot would just abandon their beliefs because the Doctor gave them a talking to looks, at best, actively naïve when the analogy the episode implies is that Islamic State would stop chucking gay men off buildings and learn to accept life as good Westerners if someone could just sit down with the boss for a wee chat. I disliked Kill the Moon’s consequence-free resolution; this is even worse. Throw in Harry Sullivan as a genocidal biological weapons manufacturer and it might be my least favourite episode of the new series.

It is partly redeemed by the opening two thirds of the episode which not only finds something useful for Jenna Coleman to do for the first time this series, but has a visual style that’s more Torchwood than Doctor Who with all the moody shots of suburban decay, the Doctor and Osgood driving through London, and a terrified Zygon victim plaintively affirming, ‘I just wanted to live here’ before committing suicide. But all the stuff with the Osgood Boxes and the replay of scenes from The Day of the Doctor leave me colder than the murderous Bonnie’s ice cream reward.

Next Time: Sleep No More