Hello! I am a librarian in training so I'd be happy to answer your question. According to the CIA World Factbook, Gambia was colonized in 1664 by the United Kingdom. The CIA World Factbook provides information on every country's history and a lot of other fun statistics, so I would recommend checking it out. It's a free online source!
The United Kingdom.
Belize gained complete independence from the United Kingdom.
Britain
It gained it from the United Kingdom in 1922.
United Kingdom
Independence from the United Kingdom 6th September 1968
Kingdom of Great Britain
Belize, who gained independence from the United Kingdom in 1981.
Grenada achieved independence from the United Kingdom on February 7, 1974.
Kenya gained independence from Great Britain.
Britain
Belize was the last country in Central America to gain independence, achieving independence from the United Kingdom in 1981.