The second season of Doctor Who saw the first changes taking place in the series' regular cast and production team.
Contemporary documentation relating to the negotiations that took place when the contracts of the four leads came up for renewal shows that the production team were keen to retain the services of William Hartnell and William Russell, but regarded Jacqueline Hill's continued involvement as less important and were disinclined to keep Carole Ann Ford in the series - in large part because the actress herself wanted to leave. In the end, Hill's agents did not push for the large pay increase that would have priced their client off the show (although she and Russell did both receive a small increase of around £16 per episode), so Ian and Barbara remained with the Doctor - at least for the time being. Susan, however, was written out, and another young girl introduced in her place.
The most important change in the production team was the exit of the original story editor, David Whitaker, and the entrance of his successor, Dennis Spooner. Spooner's tenure was to be relatively short, and by the end of the season he himself had left and passed on the reigns to Donald Tosh.
A further notable development was the departure of associate producer Mervyn Pinfield (who made his last contribution in this role around the time that The Dalek Invasion of Earth went into studio, although he continued to be credited up until the end of The Romans). No new associate producer was appointed as it was considered that Verity Lambert had by this time fully justified Sydney Newman's faith in her and no longer needed such assistance.
Doctor Who's second season had seen it consolidating and building upon the success of the first and becoming one of the UK's most popular series. Producer Verity Lambert and new story editor Dennis Spooner had been determined to keep it fresh and to stretch its dramatic boundaries, and this had resulted in it venturing into previously unexplored territory such as with the overt humour of The Romans and The Chase, the pseudo-historical content of The Time Meddler and the downright weirdness of The Web Planet.
By the season's end, only William Hartnell still remained of the four original leads, while in the production office only Verity Lambert still survived from the team responsible for launching the series. Season three would see further behind-the-scenes changes taking place, and an even greater variety in the content of the stories.