Doctor Who: Every Regeneration Ranked From Worst To Best
11. The First Doctor (The Tenth Planet)
William Hartnell is the reason we have regeneration today.
His failing health caused huge panic among the writers of Doctor Who, until the idea of changing the Doctor's face was suggested. And with that, a TV institution was born.
The First Doctor's regeneration is a very simple one. At the end of the Tenth Planet, the Time Lord's old body finally catches up with him, and he collapses. Remarking that his body has worn out, the Doctor shuts his eyes and transforms in a brilliant flash of white light.
It's an incredibly simple regeneration, but what did you expect from their first attempt? The show was still working this mechanic out, and needed to establish it in this episode. And that's exactly what they did - no bells, no whistles.
It might be unremarkable to look at these days, but considering the time that it took place and the impact it has had on the show today, this is a very important piece of television.