What does the new Doctor Who trailer tell us about episode three?

Doctor Who loves its well tailored villains – just think of the Silence – but this new monster bears more than a passing resemblance to the Whisper Men that palled around with the Great Intelligence. These incorporeal baddies seem to be hunting the Doctor and friends, using a harpoon gun like a rifle. Coupled with the top hat, there's a real 'gentleman ghost' vibe to them, so until we have an official name we're going to call the main guy Maxwell Aloysius P'Oltergus.

The Doctor notes that they are trapped in a an isolated station miles underwater, facing a hostile force. "Yes," the more academic Who fans will be nodding now, "a classic Base Under Siege set-up."

Then they'll finish their glass of red wine and settle back into their bubble bath.

You can have it in any colour you want, as long as it's black.

What can they mean? Clara looks confused, why can't she read them with the Tardis's telepathic translation? This is all starting to feel quite Impossible Planet-ish.

Yes, turns out they weren't the one-time joke we thought they might be in The Witch's Familiar. Is the screwdriver gone forever? Will the Doc be rocking sunglasses inside, Bono style, from now on?