"But if the Improper Use of Magic lot get their hands on Mad-Eye, he’s had it -- think of his record"
-- Amos Diggory about Mad-Eye Moody (GF11)
The Improper Use of Magic Office is a division of the Department of Magical Law Enforcement in the Ministry of Magic. The office deals with incidents of magic being used inappropriately, particularly in cases where Muggles are involved. The offices are located on Level Two of Ministry headquarters (OP7). The office registers wizards who can turn themselves into a Animagi (GF26).
The Office sent Harry Potter warning letters when the use of underage magic was detected at the Dursleys’ house (CS2, OP2). The letters are signed by Mafalda Hopkirk, an assistant (CS2, OP2, DH12). Later, Hermione Granger uses Polyjuice Potion to transform herself into Mafalda in order to get into the Ministry – and is then drafted for recordkeeping by Dolores Umbridge (DH12).
Mrs Weasley worries that her sons Fred and George will run foul of this office if they keep on getting into trouble, especially after she discovers semi-legal items being marketed as “Weasleys’ Wizard Wheezes” (GF5).
Although the date printed on the second Daily Prophet Newsletter (DP2) is 8 February 1999, the timeframe for this event is 1992-1993.