Doctor Who: Why Each Doctor Was Forced To Regenerate

Even though the concept of regeneration has been around since 1966, there's still an element of mystery surrounding the process.

For example, it's still not 100% clear how the Doctor chooses their next face. In most cases, it seems to be completely random, like the character has no control over what their next incarnation will look like (in his very first scene, the Eleventh Doctor expresses dismay at the fact that he's still not ginger), but in some cases, we see that Time Lords are in fact able to influence the outcome of their regenerations.

Just look at the Twelfth Doctor, who subconsciously chose his own face to remind himself that he must save as many lives as possible. And way before this, the Second Doctor was actually given some options to choose from before regenerating into the Third Doctor, almost like a character creation option in a Sims game.

And this leads us to the cause of his regeneration. After being put on trial for breaking the Time Lords' non-interference policy, the Second Doctor is sentenced to an exile on Earth, along with a forced regeneration. At this point, he's presented with several options for new faces, but he rejects all of them, so the Time Lords decide for him.

Cue a trippy sequence in which Patrick Troughton pulls a load of weird faces, and the Third Doctor emerges from the TARDIS on planet Earth, collapsing to the ground.