Doctor Who's huge Timeless Child twist poses a big question about the Doctor

The episode revealed that the Doctor herself was the Timeless Child – having been found on a remote planet and adopted by Gallifreyan scientist Tecteun, the child's natural ability to regenerate was later extracted and used to found Time Lord society.

The Doctor, then, is not from the Time Lords' home planet of Gallifrey – something accepted as fact by fans ever since it was first established in 1969, in the story The War Games.

Instead, the Doctor/Timeless Child is from somewhere else entirely – though not the planet where she was discovered by Tecteun, with The Timeless Children revealing that the child had travelled there through the Boundary, a pathway between galaxies, and had actually originated at some other unknown point.

As if establishing that there were an unknown number of incarnations of the Doctor before William Hartnell's 'first' wasn't big enough, the undoing of the character's Gallifreyan roots is a huge reveal, one that's sure to prove divisive amongst fans.

But in pulling the rug out from under us, throwing out everything we thought we knew, Doctor Who has actually reverted to its original status quo. Now, for the first time in more than 50 years, we have no idea who the Doctor really is or where they came from, giving some meaning back to the 'Who?' in the show's title.

And after all, where's the fun in knowing everything?

https://www.youtube.com/watch?v=bB5P4-nKaHc

Doctor Who will return to BBC One this festive season