Decree for the Reasonable Restriction of Underage Sorcery

Mafalda Hopkirk's Letter of 1995 warning Harry Potter about his breach of the Decree.

"Dear Mr. Potter, We have received intelligence that you performed the Patronus Charm at twenty-three minutes past nine this evening in a Muggle-inhabited area and in the presence of a Muggle."

— Mafalda Hopkirk's letter adressed to Harry Potter on 2 August, 1995

The Decree for the Reasonable Restriction of Underage Sorcery is a bylaw of the Ministry of Magic, written in 1875, which bans the use of underage magic outside of school. The Decree is enforced by the Ministry's Improper Use of Magic Office. The restriction is for wizards and witches who are under the age of seventeen, and who still have The Trace on them. Although young wizards and witches are not allowed to use magic outside of school, the Ministry does recognise that they may have to use magic in certain situations such as self-defence. In addition, young children of below school age are technically exempt from the rule since they usually have little or no control over the magic they perform.

"In the matter of Harry Potter, the law clearly states that magic can be used before Muggles in life-threatening situations."

— Albus Dumbledore at Harry's Hearing

Paragraph C of the cause states that it is a crime to knowingly perform magic in a Muggle-inhabited area and in the presence of a Muggle. However, Clause 7 states that magic can be used in front of Muggles in exceptional circumstances, including situations when the life of the witch or wizard is threatened, or the lives of other witches, wizards and Muggles are threatened.

Also, it seems that a certain high-authority person may give permission for an underage student to perform magic under circumstances, as Hogwarts Headmaster Albus Dumbledore gave 16-years old Harry Potter such under the chance of an attack.

Known breaches of the Decree for the Reasonable Restriction of Underage Sorcery

Offender	Crime	Date	Action taken	Notes
Lily Evans	Magic	Unknown	Received a few warning letters	None of her warning letters were “too serious”
Hermione Granger	"A few simple spells"	Summer of 1991	No action taken	Hermione told Harry Potter and Ron Weasley just prior to their first year at Hogwarts that she had successfully cast a few spells, but apparently, she received no notice or warning about this being banned.
Harry Potter	Illegal use of a Hover Charm	July, 1992	Official warning	The Hover Charm was actually produced by the House-elf Dobby.
Harry Potter	Illegal use of the Inflating Charm on his "Aunt" Marge	July, 1993	No action taken	Action not taken due to the recent escape of Sirius Black from Azkaban, and the need to keep Harry safe. Additionally, this was considered "accidental magic."
Harry Potter	Illegal use of the Patronus Charm in front of a Muggle	2 August, 1995	Expulsion from Hogwarts School of Witchcraft and Wizardry, later rescinded and given a hearing	Acquitted of all charges due to the fact that he technically did not break any rules. Dolores Umbridge was the one who secretly orchestrated this incident as part of the smear campaign against Harry.

Appearances

• Harry Potter and the Chamber of Secrets (First appearance)
• Harry Potter and the Chamber of Secrets (film) (Mentioned only)
• Harry Potter and the Prisoner of Azkaban (Mentioned only)
• Harry Potter and the Prisoner of Azkaban (film) (Mentioned only)
• Harry Potter and the Order of the Phoenix
• Harry Potter and the Order of the Phoenix (film)

Behind the scenes

• In the film version of Harry Potter and the Philosopher's Stone on the Hogwarts Express, Hermione casts the Oculus Reparo spell to fix Harry's glasses - and she does it again in public in Diagon Alley in the film version of Harry Potter and the Chamber of Secrets. There is no indication that she got into trouble for either non-school use; it is possible the Reparo spell was considered too mundane or harmless to violate the so-called "Reasonable Restriction." And the first use of the spell might have been ignored if the train is considered an extension of the school. This latter point is supported by Harry Potter and the Order of the Phoenix in which Ginny Weasley casts the Scouring Charm aboard the Express without penalty.
• In the film version of Harry Potter and the Chamber of Secrets Harry did not receive a warning for the illegal use of a Hover Charm which caused a continuity error with the following films due to the fact that the book version caused the Dursley family to learn that Harry cannot use magic outside of school.
• The film version of Harry Potter and the Prisoner of Azkaban has Harry using the spell Lumos Maxima which was invented for the films despite his using it at the time would had a warning sent to him since he used it while at the Dursley's house.
• In Harry Potter and the Order of the Phoenix, during the Disciplinary hearing of Harry Potter, even though Harry had been given an official warning in 1992, and that he had not punished Harry personally in 1993, Cornelius Fudge attempted to use these incidents to expel Harry from Hogwarts despite those incidents being completely irreverent to his recent illegal use of magic. In addition, despite Dobby being a witness in the underage magic incident in 1992, Fudge refused to let him testify due to Dobby being a House-elf.