Because the political parties contesting the March 1961 elections had declared their intent to seek full independence, another constitutional conference was held in London in 1963. The conference led to the establishment of full internal selfgovernment under a constitution that took force on January 1, 1964.

The changes introduced by this constitution significantly reduced the powers of the governor, transformed the Executive Council into a cabinet headed by a premier, and established a bicameral National Assembly, composed of a House of Representatives and a Senate. The House of Representatives had eighteen members, all of whom were elected. The Senate had eight members, all appointed by the governor after consultation with majority and minority party leaders and other "suitable persons." The Senate's powers were limited to ratifying bills passed by the House or delaying, for up to six months, bills with which it disagreed (but for only one month on financial bills). General elections had to be held at least every five years on a date determined by the prime minister. The governor was still appointed by the crown but was now bound by the recommendations of the cabinet in executive matters. The leader of the majority party in the House of Representatives was to be appointed premier by the governor. Members of both the House and the Senate were eligible for appointment to the cabinet.

The constitution of 1964 established internal self-rule, and Britain had conceded the readiness of the colony for independence as early as 1961. But Guatemalan territorial claims against Belize delayed full independence until 1981 (see Decolonization and the Border Dispute with Guatemela , ch. 6).

Data as of January 1992