The story is pretty clearly pitting those who countenance killing as a means to an end – Salamander, Benik, and Kent – against those who value life more highly: the Doctor, Bruce and Swann. An unlikely alliance between the Doctor and Bruce to expose Salamander starts to come together at the moment when Salamander’s own carefully-laid plans begin to fall apart because of his own over-confidence.

To be fair, those plans seem a bit absurd even for a Bond villain: hoodwinking a whole community into living in a nuclear bunker and using them to cause natural disasters is a car crash waiting to happen. Why not just pay someone instead – or get Benik to do it? It’s not like he seems to have any scruples as his convincingly nasty torture of Victoria shows. And to have the whole plan exposed by a torn-off bit of newspaper advertising a holiday cruise is pretty weak. I’m not sold on any of the bunker plot.

In contrast, the bits on the surface remain pretty gripping. The Doctor winning a grudging benefit of the doubt from Bruce is solid. Even better is him impersonating Salamander to fool Jamie and Victoria (both wearing jumpers and kilts like a Scottish Eurovision entry) into spilling the beans in front of Bruce, before snapping back to normal when Victoria threatens to give him a slap, and convincing them of his credentials by playing an invisible recorded (to Bruce’s evident bafflement). As they haven’t shared a scene for almost a month, it plays a lovely reunion.

The direction remains good, with occasional flashes of inspiration – the cut from Salamander picking up a lead pipe to cosh Swann, to Astrid smashing a window in Kent’s caravan conveys brutal violence without actually having to show it. But the overall sense is of a story slowly unravelling rather than barrelling towards a climax.

Next episode: The Enemy of the World – Episode 6