10 Moments That Almost Killed Doctor Who

Whenever an actor decides it's time to hand in their keys to the TARDIS and leave the show, they regenerate. It's an iconic aspect of Doctor Who and has made it possible for the series to continue with the same character (often played by a charming Scotsman) for well over six decades.

One actor leaves, another takes their place, and you have a brand-new Doctor! It's a perfect characteristic of Time Lord biology that makes it possible, but it wasn't always part of the show. In fact, before there was even any talk of a Second Doctor, there was a time when there wasn't actually a plan to keep the series going once original Doctor William Hartnell left.

As one of Hartnell's final companions Anneke Wills explained in 2016:

"We knew Bill [Hartnell] was going to finish, that he was gone, and then there were discussions... 'OK, is that the end of the show or shall we have another actor? Shall we have an actor who looks like Bill, or shall we have a completely different actor?'"

Fortunately the decision was of course made to continue the show with a new lead actor, which itself raised a whole new crop of concerns. Would the public accept a new Doctor once Hartnell left? Harnell was the Doctor, so it was anyone's guess.

Those concerns were swiftly put to rest when Patrick Troughton's amazing, charismatic take on the character gave Doctor Who new life, earning it a stay of execution for the next three years.