The longer this series goes on, the more likely it seems that someone might raise a hand and suggest that this scorched earth policy on slightly enchanty locals has been the source of almost every problem for the regime in the last three series.
After lurching entertainingly around medieval legends and high-school romance plots for most of the season, the show seems to have snapped into a more straightforward fantasy mode.
The rulers in question are converging on Camelot for a peace conference of the kind I have a strong suspicion never happened, either in the Arthurian legends or in medieval history, but Merlin has cunningly wriggled its way into one of my many historical blindspots this week, and I’m not in a position to condemn it.
At first glance it seems absolutely obvious what is going on here: to whit, some pretty repulsive misogyny. The potion with Catrina has to take to keep her looking beautiful has a lot in common with the centuries-old anxiety around cosmetics, a handy stand-in for the ideas that women are liars, that they spend their time trying to trap men and that there is something inherently repulsive about women’s bodies.