The hostility of Sudan's southerners toward the northern Arab majority surfaces violently when southern army units mutiny in August 1955 to protest their transfer to garrisons under northern officers.

The rebellious troops kill several hundred northerners, including government officials, army officers, and merchants

The government quickly suppresses the revolt and eventually executes seventy southerners for sedition, but this harsh reaction fails to pacify the south, as some of the mutineers escape  to remote areas and organize resistance to the Arab-dominated government of Sudan.

In particular, they resent the imposition of Arabic as the official language of administration, which deprives most of the few educated English-speaking southerners of the opportunity to enter public service.

They also feel threatened by the replacement of trusted British district commissioners with unsympathetic northerners.

After the government replaces several hundred colonial officials with Sudanese, only four of whom are southerners, the southern elite abandons hope of a peaceful, unified, independent Sudan.