Why Every Lead Actor Left Doctor Who
11. Jon Pertwee
The Third Doctor's era brought big change to Doctor Who. The show was now in colour, the Doctor was stranded on Earth working with his UNIT family, and iconic characters like the Master, Sarah Jane Smith, and Jo Grant were introduced.
They say that nobody likes change, but in this case, it was a big hit, with Doctor Who enjoying something of a renaissance after ratings had dipped towards the latter end of Troughton's run.
This success might be why Pertwee remained in the role for longer than either of his predecessors, completing five full seasons instead of the usual three. An incredibly positive tenure overall then, but one that was tinged with sadness by the time it concluded.
After the tragic death of his good friend and Master actor Roger Delgado in 1973, Pertwee was motivated to head for the exit. Various cast and crew members were also leaving the show, and Pertwee decided it was time for him to do the same. His request for a significant payrise had also been declined, which further reinforced his decision.
1974's Planet of the Spiders was the first story to use the term "regeneration" to describe the Doctor's face-changing process, and it was here where Pertwee bowed out of the role.