By July [1955] the Singapore Chinese Middle Schools Students' Union had begun planning a campaign of agitation against the government. The Lim Yew Hock government moved first, however, dissolving seven communist-front organizations, including the student union, and closing two Chinese middle schools. This touched off a protest sit- in at Chinese high schools organized by Lim Chin Siong that ended in five days of rioting in which thirteen people were killed. Troops were brought in from Johore to end the disturbance, and more than 900 people were arrested, including Lim Chin Siong, Fong Swee Suan, and Devan Nair. The British approved of the Singapore government's tough action toward the agitators, and when Lim Yew Hock led a delegation to London for a second round of constitutional talks in March 1957, the Colonial Office proposed a compromise on the internal security issue. The Singapore delegation accepted a proposal whereby the Internal Security Council would comprise three Singaporeans, three Britons, and one delegate from what was soon to be the independent Federation of Malaya, who would hold the casting ballot. The Singapore delegation returned to a hero's welcome; the Legislative Assembly accepted the proposals, and a delegation was scheduled to go to London in 1958 for a third and final round of talks on the new constitution.