Attack in Little Whinging

The Attack at Magnolia Crescent occurred after the Ministry of Magic insisted that the Return of the Dark Lord never occurred. Wanting to expel Harry Potter, Dolores Umbridge sent two Azkaban prison guards at Little Whinging.

"Dementors? In Little Whinging? Whatever next? The whole world's gone topsy-turvy."

- Arabella Figg

The two dementors arrived and attacked Harry and his cousin Dudley Dursley, while Harry teased Dudley. Unfortunately, Dudley walked right into one dementor, while Harry repelled the other. Once the other was gone, Harry sent his Patronus at the one tackling Dudley. Just afterwards, the Squib Mrs. Arabella Doreen Figg arrived and led Harry back home, ranting on about the sneak thief Mundungus Fletcher.

Aftermath
"Dear Mr. Potter, The Ministry has received intelligence that at 6:23 this evening, you performed the Patronus Charm in the presence of a Muggle, out of clear violation of the Decree for the Reasonable Restriction of Underage Sorcery. You are hereby expelled from Hogwarts School of Witchcraft and Wizardry. Hoping you are well, Mafalda Hopkirk"

- Mafalda Hopkirk

After Harry arrived, he was given a letter giving him a disciplinary hearing on August 12, 1995 for using a Patronus Charm "in the presence of a Muggle".