Harry Potter directors had to leave crucial plot point out of movie which impacted the entire storyline

There are a number of scenes from the Harry Potter books which didn't make it to the movies and this has pretty much been a point of complaint for fans since the films were released.

While Harry Potter fans generally like the movies, there are some who think it's a bit unforgivable that certain moments like Hermione's establishment of S.P.E.W didn't make it onto the big screen.

While some of these cuts are understandable from a movie making perspective since they don't have enough time to fit everything in, there will always be fans lamenting the loss of moments from the books.

Then there are the cuts, which actually mean they have to put new things in later movies because they sliced the explanation out of a previous film.

In Harry Potter and the Half Blood Prince, Harry grievously wounds Draco Malfoy with the 'sectumsempra' spell which he read about in his heavily annotated copy of Advanced Potion Making, which actually used to belong to his teacher Severus Snape.

Harry learned where this was earlier in the books than the movies. (Warner Bros.)

Harry doesn't know what the spell does, only that it's 'for enemies', and ends up giving Malfoy some serious bleeding wounds which almost killed him.

Snape steps in to cure Malfoy and in the book he then orders Harry to bring him his copy of Advanced Potion Making, which Mr Potter doesn't want to do.

Book Harry takes his textbook to the Room of Requirement to stash it there and passes off Ron's copy as his own, and while he's in the room, he takes notice of a bust with a wig and a tiara on it - which sticks in his memory.

Fast forward to the next book, Harry Potter and the Deathly Hallows, and Harry learns that Lord Voldemort is a complete moron because instead of making his horcruxes random objects nobody could ever find he's actually used very recognisable artifacts including the diadem of Rowena Ravenclaw.

When Harry is trying to find the diadem, he remembers the tiara he saw in the Room of Requirement and faster than you can say alakazam he figures out he already knows where he needs to look.

However, in the movies Harry (Daniel Radcliffe) doesn't stick around in Half Blood Prince and runs away like the big brave boy who lived, with Hermione (Emma Watson) then telling him to hide the book.

In the film Ginny (Bonnie Wright) goes with him to the Room of Requirement and gets Harry to close his eyes while she hides the book so he won't know where it is.

As such, he never actually sees Ravenclaw's diadem in there, and two movies later in Deathly Hallows Part 2, this change from page to screen came back to bite the filmmakers in the a**e as they now had to find a way to teach Harry about it.

"You know, if the filmmakers hadn't cut something out of the adaptation two movies ago we wouldn't even need to have this conversation." (Warner Bros.)

As they'd left the plot point out of the previous film, they needed to bring in a scene where Harry goes to ask the ghost of Helena Ravenclaw (Kelly Macdonald), Rowena's daughter, where to find it.

So while Hogwarts is under siege from Lord Voldemort (Ralph Fiennes), Harry has to go on a ghost hunt to track down information he already knew in the books to stop the noseless wonder.

The upcoming Harry Potter TV series is apparently going to be a more faithful adaptation of the books, so perhaps the original plot point will be inserted back in and Harry will know where Ravenclaw's diadem is instead of having to ask a ghost.