7 Times Doctor Who Almost Died

7. William Hartnell's Departure

Whenever an actor decides it's time to call it quits on the TARDIS and leave the series, they regenerate. It's a well-known aspect of Doctor Who, and it's what has made it possible for the series to continue with the same character for more than half-a-century.

One actor leaves, another takes their place, and you have a new Doctor! It's a perfect characteristic of Time Lord physiology that makes it possible, but it wasn't always a part of the show. Before there was any talk of a 2nd Doctor, there wasn't a plan to keep the series going once William Hartnell left.

When Hartnell let the studio know he was leaving, that spelled doom for the show. When it was determined that another actor could theoretically take his place, the concern was with the British public — would they accept a new Doctor once Hartnell left? Harnell was the Doctor, so it was anyone's guess.

Fortunately, Patrick Troughton's amazing charismatic take on the character ensured the series would continue with a "new" Doctor. It was a close call, and the show almost ended up being canceled, but it got another three years with Troughton, earning it a stay of execution.