The Morant Bay Rebellion of 1865 made Britain strength the control of Jamaica through makeing Jamaica a Crown Colony of Britain in 1866. Under the Crown Colony system, the nominal government was consisted of the legislative Council and the executive Privy Council members of both chambers of the House of Assembly. But the governor appointed by British government exercised effective power overh the island. Although British government reintrouduced limited self-rule to Jamaica after 1884, the highest power was controlled by governor. In fact, it was British officials and upper-class whites who ruled the island.
In the twentieth century, a growing mulatto middle-class with increasingly impressive education and property began to opposed the Crown Colony rule and demanded for reponsible self-government. They thought that the colony office didn't protect their economic status efficiently and was indifferent to hear their demands of politic rights. These dissatisfaction with colony office and racism led to the rise of nationalism in Jamaica. More and more people of color realized that they should set up a responsible self-government to protect their benefits from the white upper-class. In the meantime, industrial revolution created a growing working class and they began to unionized themselves to demand a self-government to protect their political and civil rights. The Great Depression exacerbated the working class's living condition and made them be more eager to overthrow the repressive government. The Riot of dock and sugarcane plantation workers in 1938 accelerated the unionization of working class and forming of politic party. The People's National Party was founded in the same year of the riot by Norman Manley and the Jamaica Labour Pary was established five years later by William Alexander Bustamante. Both parties struggled for self-demernation and self-government of Jamaican.
The Riot of 1938 also made British gave more rights of self-government to Jamaica. In 1944, the first universal adult suffrage elected a autonmous governemnt in Jamaica. Bustamante became the first premier of the autonomous government. However, the ultimate power remained in the hands of the governor.
From 1944 to 1962, Jamaica was in the period of constitutional decolonizaiton. It meant that Britain gradually granted the colony more self-government under periodic constitutional changes. For examle, the admendment to the constitution granted the right of electing ministers to the House of Representative in 1953. In 1957, the cabinet government was established.
Jamaica joined the West Indies Federation in 1958 but withdrew in 1961. In 1962, Jamaica became a full independent country from Britain and Bustamante became the first prime minister.
However, Jamaica still kept some special relationship with Britain. It was a member of Commonwealth of Nations and the British queen Elizabeth II was recognized as the head of nation.
Source:
1. Jamaica-history, Countries Study. www.country-studies.com/Jamaica-history.html
2. Munroe, Trevor, The Politics of constitutional decolonization: Jamaica, 1944-1962, University of the West Indies, 1972