Doctor Who

7.20PM, BBC1

The third episode finds the Tardis landing in London on the day of the last great frost fair, an event the Doctor (Peter Capaldi) is keen to enjoy. ‘It’s 1814,’ says an incredulous Bill (Pearl Mackie, right, with Capaldi), pointing at her skin. ‘Slavery is still totally a thing. It might be, like, dangerous out there.’ As she soon discovers, racism was indeed rife in Regency England – but at least, it was out in the open. A more insidious threat, however, is whatever is lurking in the frozen River Thames, waiting to draw its victims beneath the ice, to their doom.