Another day, another reminder of the great 2016 Doctor Who drought: it’s the anniversary of one of the greatest moments of modern Doctor Who, a moment one over four and a half billion years in the making.
You guessed it, it’s one year to the day since series nine episode Heaven Sent aired, where the Doctor escaped the mysterious veiled creature after punching his way through the 400-times-stronger-than-diamond Azbantium wall into Gallifrey.
Can’t quite remember why he found himself in such a pickle? Peter Capaldi’s Doctor is teleported into an elaborate torture chamber, one in which the rooms reset after a certain period of time, with the only routes to freedom being a) smashing through the thick Azbantium wall, or b) revealing his secrets.
So the Doctor uses the rules against the prison. Realising that resetting the teleporter means another version of himself is stored in its memory, waiting to emerge, he starts playing a long, long game: running the maze over and over again just to punch that final wall once or twice, before dying and starting the process again.
It was a very very clever plot, but not one that came without some very difficult questions. Could the Doctor actually punch through a wall of diamond? How old is the Doctor after the episode? And where did this entire episode actually take place?
All very complicated questions, partially confronted by showrunner Steven Moffat here. But we can help you with one of the biggest Who questions of the moment right here: when is the next episode of Doctor Who? Simple answer: Christmas Day.