10 Doctor Who Episodes That Accidentally Changed The Show Forever

The second appearance of Robert Holmes on this list, and once again it's a big one – perhaps the biggest of all.

In the climax of his 1976 story The Brain of Morbius, the Doctor and Morbius (a Frankenstein’s Time Lord whose head is a brain in a fish bowl – peak '70s television) have a "mind-bending contest," during which we see Morbius, the Doctor, and his three previous incarnations.

In addition, eight unknown faces were also shown, beginning one of the longest-running debates in Doctor Who fandom. Were these faces previous incarnations of the Doctor from before William Hartnell? Or something else entirely?

The show itself carried on treating Hartnell as the ‘original’ incarnation of the Doctor, particularly during Moffat’s tenure as showrunner, where references to the Doctor's ‘numbers’ became common.

That was until 2020’s The Timeless Children, where Chris Chibnall established that yes, those mysterious faces seen 44 years previously were in fact the Doctor, who had lived countless other lives pre-Hartnell.

For all the fallout and controversy that followed this massive revelation, it’s interesting to think that Chibnall was only picking up on an unused plot thread set up nearly half a century previously.