It was discovered among Dahl's paper's following his death in 1990 and reveals new characters and the original names of those featured in later drafts.
The excerpt shows Dahl originally plotted to send Charlie into the chocolate factory with eight children instead of four, while familiar characters such as Augustus Gloop given different monikers, such as Augustus Pottle.
Characters named Tommy Troutbeck and Wilbur Rice meet a sticky end when they ignore Wonka's warnings and ride railway waggons carrying fudge to The Pounding and Cutting Room.
It also reveals Charlie originally went into the factory with his mother rather than his grandfather.
Quentin Blake, best known for illustrating Dahl's novels, told the BBC: "I know that he rewrote and rewrote many times. For this last chapter about the vanilla fudge mountain he is leading a group of people who are not in the final book.
"It is interesting to see something at an earlier stage, you know, what happened in the cooking as it were. That's rather fascinating."
- Independent