Malaysia–Singapore border territories when Johor became a British protectorate while Singapore remained a British crown colony. On 31 August 1957, the Federation of Malaya (which consisted of only Peninsular Malaysia), which included Johor as a component state, became independent and the Johor–Singapore border again became an international boundary between the sovereign state of Malaya and the self-governing British territory of Singapore. On 16 September 1963, Singapore merged with and become a component state of the Federation of Malaysia, rendering the border between two component states of Malaysia. The border again became an international border when Singapore chose to be separated from Malaysia
Federation independence from the sovereign state, which only takes care of their foreign relations and defence. However, they are neither considered to be part of it, nor recognised as sovereign or associated states. The distinction between a federation and a unitary state is often quite ambiguous. A unitary state may closely resemble a federation in structure and, while a central government may possess the theoretical right to revoke the autonomy of a self-governing region, it may be politically difficult for it to do so in practice. The self-governing regions of some unitary states also often enjoy greater autonomy than those of