Gambian President Yahya Jammeh at UN
3 October 2013 Last updated at 17:16 BST
The Gambia's decision to withdraw from the Commonwealth 48 years after joining is something to "very much regret", the UK Foreign Office has said.
The west African nation branded the 54-member grouping, which includes the UK and most of its former colonies, a "neo-colonial institution".
The withdrawal was announced on state TV, but no other reasons were given.
Speaking at the UN General Assembly last week, Gambian President Yahya Jammeh said the Gambia was determined to "defend its independence and dignity by whatever means necessary".