New Doctor Who companion Bill (Pearl Mackie) is still getting to know the strange old alien she’s started travelling with – and it looks like she’s about to see his darker side.

In a new next time trailer for next week’s 1814-set episode Thin Ice, we see the pair enjoying the thrills of London’s last Frost Fair on the frozen Thames (“Regency England – bit more black than they show in the movies” Bill quips), only for things to go awry as a monster lurks under the ice.

But despite the danger down below, the presence of a sinister villain (played by Nathan Barley himself, Nicholas Burns) and a cockney urchin making off with the Doctor’s sonic screwdriver (see below), it seems Bill’s more concerned with her erstwhile tutor’s mysterious past. 

“Have you ever killed anyone?” she asks the Doctor point blank – and while fans will be sure to argue the nuances of whether offing a few Daleks and baddies REALLY counts as murder, we’re betting Bill won’t take the truth too well…

Doctor Who continues on BBC1 next Saturday at 7.20pm