Inter-Departmental Memos

• Type: Magical Communication Device
• Owners: Ministry of Magic
• Maker: Unknown

Inter-Departmental Memos are pieces of pale violet parchment enchanted for use as an internal messaging system within the Ministry of Magic. When a message is written and addressed, the parchment magically folds itself into the shape of a paper aeroplane. Each memo has a small, silver stamp on one wing that reads “Ministry of Magic”. They are self-propelled and navigate the corridors, lifts, and offices of the Ministry headquarters to find their intended recipient.

The primary function of these memos is to transport written messages quickly and cleanly between departments. They were introduced to replace the use of owls for internal mail, which, according to Arthur Weasley, caused a considerable mess from droppings and feathers. To send a memo, a wizard or witch writes their message, along with the recipient's name and department, on the violet parchment. The memo then automatically folds and flies off to its destination. They are charmed to be self-guiding and can locate individuals anywhere within the Ministry building. Upon arrival, a memo will typically land on the recipient's desk or can be caught directly from the air. The memos are reusable; once a message has been read, the recipient's name can be crossed out and a new one added for a new delivery.

The exact date of the memos' introduction is unknown, but they were firmly established as the standard for internal communication by the time of Harry Potter's disciplinary hearing in Harry Potter and the Order of the Phoenix. Arthur Weasley explained their function to Harry during this visit, highlighting them as an improvement over the previous owl-based system. They continued to be used throughout the Second Wizarding War, serving the administrations of Cornelius Fudge, Rufus Scrimgeour, and the Voldemort-controlled Ministry under Pius Thicknesse. During this latter period, they were used to deliver oppressive summons and decrees as part of the new regime's agenda.

Inter-Departmental Memos first appear in Harry Potter and the Order of the Phoenix, where they serve as a distinctive world-building detail that defines the atmosphere of the Ministry of Magic—a place where mundane bureaucracy is executed with magic. In Harry Potter and the Deathly Hallows, the memos become a critical plot device during the trio's infiltration of the Ministry. While disguised, Harry Potter catches a memo sent by Mafalda Hopkirk to Dolores Umbridge, which reveals that Arthur Weasley's family is being monitored and that his wife is being interrogated by Yaxley. This information forces the trio to alter their plans and adds significant tension to their mission. Later during the infiltration, Harry uses a blank memo as an act of personal defiance against Dolores Umbridge. He writes “I must not tell lies“—the phrase she had forced him to carve into his own hand—and sends it flying into her office, using the Ministry's own system to confront her.

• In the film adaptation of Harry Potter and the Order of the Phoenix, the memos are vividly depicted as a massive swarm of paper aeroplanes zipping through the Atrium. A memorable scene also shows hundreds of them pouring out of Dolores Umbridge's office door. (film)
• The memos are a prime example of J.K. Rowling's world-building, blending a familiar, mundane object (an office memo) with a whimsical magical function to create something uniquely part of the wizarding world.