I recently watched a few classic Doctor Who episodes from the 80's and earlier during Twitch's streaming event and at one point I was rather surprised to hear music in background that appeared to be an earlier version of the later Series 6 track The Majestic Tale (of a Madman in a Box):
I'm wondering whether this was something edited in/added later (I think it was an actual episode, but might have been filler clips between; which were 100% Classic Who though).
So was this track based on some music from the classic series? If so, which one? Are there other examples of reused tracks (except the main theme for obvious reasons)?