‘I have my good days and my bad days.’ I took an intense dislike to this one the first time I saw it and hadn’t rewatched it since 2011. I don’t remember why: on a second viewing it’s poor, but inoffensive. Its main flaws are a plot that relies on the Doctor repeatedly guessing incorrectly to string out a thin story, and a sense that some explanations are missing.

On the first point, the Doctor guesses, the mysterious Siren uses blood, water and reflections, and that the creature is dangerous until he decides it isn’t and they should all prick their fingers and enter its realm. There is a distinct whiff of this all being made up as it goes along. The Doctor admits he has off days, and Matt Smith doesn’t seem entirely sure what to do with this, as the Doctor flips from finding it all jolly japes to angrily complaining at Avery to standing about letting Amy do the hard work of saving Rory, and once again (after he abandoned Abigail to disease) refusing to provide the medical assistance that would surely have cured Toby.

This isn’t helped by choppy editing, which sees Lee Ross’ Boatswain vanish from the plot, and Avery’s crew suddenly released from suspended animation when Amy has to convince the Siren to sign over Rory to her care. Or other random choices, like Amy taking time to dress up as a pirate and mucking about when she’s meant to be rescuing the Doctor and Rory from being made to walk the plank.

The pay off, that it’s all an Emergency Medical Hologram gone wrong, is a typical Moffat “broken button” plot. But Avery and his crew flying off into space on an advanced ship is bizarre. Has the Doctor really let a gang of murderous pirates loose on the galaxy, just because Avery sounded vaguely regretful in one conversation?

It’s hard to shake the feeling that this one needed a rewrite to clarify motives, build out the story, and address the out of character moments – particularly to give Hugh Bonneville a better role than the astonishingly subdued pirate captain he plays here (he’s more yo-ho-ho in Bonekickers). On the other hand, as Saturday-night entertainment it’s got pirates, a decent Siren, and some impressive night-time location filming. The audience appreciation scores testify it looks and sounds fine to anyone half watching. Viewers liked this better than Love & Monsters.

Next Time: The Doctor’s Wife