The TARDIS is as integral to the story of Doctor Who as the Time Lord himself. In fact, you could argue that it’s almost another character, since it’s been a constant throughout the show’s 54 year history, but changes with each new incarnation of The Doctor. The magical police box – which is bigger on the inside than the outside and can travel through time and space – has been the backdrop for some of the most memorable moments from the BBC’s flagship drama series, but now, eagle-eyed fans have spotted something that might provide an important visual clue for the plot of the upcoming Christmas Special.
In a still picture from the episode – which features David Bradley as The First Doctor, standing at the control panel of the TARDIS – many have observed that the wall behind him does not actually match the TARDIS interior of The First Doctor (which had a circular pattern), but rather reflects the wall seen in the 50th Anniversary Special, starring Matt Smith’s Eleventh Doctor. In it, he meets The Curator, played by Tom Baker (The Fourth Doctor), and they’re against a TARDIS-like backdrop with those same hexagonal sections.
There are many points that could arise from speculation about the wall in these images, the most notable of which is a possible callback to the plotline of that 50th Anniversary Special (The Day Of The Doctor). The episode saw The Doctor return to save Gallifrey, and its civilization, from destruction in the Time War by freezing the planet in a single moment in time, in a parallel universe. All of the Doctors united in that endeavour, and archive footage of the character’s previous incarnations was combined with new footage of the Tenth, Eleventh, and War Doctors. It also included the first – albeit brief and partial – appearance of Peter Capaldi’s Twelfth Doctor.
So, it might be quite fitting for the actor to depart the show upon the same plot thread with which he arrived – and Doctor Who is a series that likes to plug past plot holes. The beauty of the show, and one of the reasons for its impressive longevity, is that its premise allows for that retrospective approach, amid its inevitable leaps forward into the future. Whether this fan theory will prove correct remains to be seen, but all will be revealed when the Christmas Special airs on December 25th.