One of Doctor Who's greatest strengths is that the series hops through time and space, with infinite possibilities for where the TARDIS will travel next. The viewer never knows what the next story will be like, with the only thing that's certain is that it won't be the same as the previous one. This was especially true in the early years of the show, when William Hartnell played the First Doctor, and the producers experimented with how far they could push the boundaries of the series.
Source：https://www.cbr.com/doctor-who-controversial-episode-the-web-planet/
