Chapter 3 of Half-Blood Prince makes it very clear that Grimmauld Place has more protections placed on it by The Order than just the Fidelius Charm:

We do not know whether the enchantments we ourselves have placed upon it, for example, making it Unplottable, will hold now that ownership has passed from Sirius’s hands.

My question is this: What's the point of these additional protections? The impression that I got from the earlier books in the series, particularly Prisoner of Azkaban, is that the Fidelius Charm's protection is flawless unless the secret-keeper leaks the secret or you're an owl (something that even the additional enchantments didn't block). Given that Dumbledore is said secret-keeper, the chance of him exposing the secret is small enough to ignore, so what other reasons were there?

  • 4
    Did you perhaps miss the part where the Fidelius charm utterly failed to protect Harry's parents and their mortal enemy turned up and murdered them in cold blood?
    – Valorum
    Nov 6, 2020 at 22:50
  • No, I mentioned secret leaking.
    – J. Mini
    Nov 6, 2020 at 22:51
  • 3
    Sure, but the point is that no magic is foolproof. Layered security is always better than a single-point-of-failure.
    – Valorum
    Nov 6, 2020 at 22:54
  • @Valorum Isn't the entire premise of everyone - including those who knew about the charm - assuming Sirius' guilt in PoA that the charm is foolproof? In fact, Flitwick's description of the charm specifically used the word "impossible". To my knowledge, PoA contained no signs of any doubt in its capabilities.
    – J. Mini
    Nov 6, 2020 at 22:55
  • 3
    CONSTANT VIGILANCE! And, of course, things change. People die, other are subverted, etc... Suspenders AND belt, when it's important.
    – K-H-W
    Nov 25, 2020 at 18:15

2 Answers 2


There was need of extra security. In Deathly Hallows a Death Eater latched onto Ronald while they were escaping the Ministry, and got sucked back to Grimmauld Place with them. It's why Hermione had to immediately Disapparate them again, and Ron got splinched.

I think the limitation of the Fidelius Charm is that you can't tell the secret, but you might be able to show it. If someone using Polyjuice Potion took on the appearance of an Order member, they could follow another member back to the hideout (which is why they constantly quizzed each other for proof of identity). Another theory is that the Imperius Curse could be used to force someone to lead others to the location.

Additionally, Dumbledore's death may have actually weakened the Fidelius Charm rather than strengthened it.

Just some random reasons why additional security might be needed. :)

  • 1
    "Dumbledore's death may have actually weakened the Fidelius [sic] Charm" That is how the charm works, actually: when a secret keeper dies, anyone and everyone they have shown the secret to then becomes a secret keeper.
    – TylerH
    Nov 25, 2020 at 19:52
  • Yaxley (death eater) grabbed onto Hermione on their attempted trip to Grimmauld Place fwiw (p 122 US Kindle edition)
    – NKCampbell
    Nov 25, 2020 at 19:58
  • Accepted, but only because of the book 7 plot point.
    – J. Mini
    Nov 25, 2020 at 20:58

Well, logically if a murderer who single-handedly killed hundreds of people is on the loose and can go anywhere in an instant, and is who knows where, then most people would rather have extra safety things to protect them. Think of a zombie invasion as an example. If you have locked all the doors and barricaded all the windows, the top is completely secure, but what's to stop a zombie from coming up through the floor? Just because the floor has ground everywhere underneath doesnt mean you feel safe. Paranoia and fear were Voldemorts biggest weapons, that's why they added extra magic to an already inpenetrable home.


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