Over the years, we've seen many talented showrunners, producers, and writers all bring fresh ideas to spice up our beloved Doctor Who.
But for all of the things that have since become staples of the show, there are an equal amount of interesting concepts that sadly failed to materialise.
With every single series going through rigorous changes and edits in the hands of producers and directors alike, oftentimes the ideas that were initially included in the scripts and proposed as concepts end up getting dropped for a variety of reasons. This can include budget limitations, availability of actors, or simply just plans that were deemed too extreme or ridiculous for Doctor Who.
And yes, it is possible for something to be too ridiculous for this show.
Not every idea that gets floated around is solid gold, mind you. There was serious chatter about killing off Sarah Jane Smith at the end of her classic run, which, needless to say, would've been a horrific mistake.
But certain unused concepts actually do sound quite good (on paper, at least), and that includes these ones...
10. Sibling Rivalry
Without a doubt, the Doctor's deadliest foe is the Master.
First introduced in 1971's Terror of the Autons, he was originally portrayed by Roger Delgado, who revelled in being Jon Pertwee's most hated enemy. Sadly though, he was feeling typecast due to the role, so he told producer Barry Letts that he wanted to end his run.
The story The Final Game was then written, which was to be Jon Pertwee's regeneration story. It would also include the shock revelation that the Master is in fact the Doctor's brother, before the Master would be killed off for good.
However, this story was never made due to a truly tragic event: while filming the miniseries Tibetan Bell in Turkey in 1973, Delgado was killed in a car crash.
This event was so traumatic that it convinced Pertwee to leave the show in 1974, with the epic final battle between the Third Doctor and the Master sadly never getting made.
The brother reveal would've added a very interesting layer to the Doctor/Master conflict, so it's a shame it never happened.