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
Combat operations in 1965 during the Indonesia–Malaysia confrontation Combat operations in 1965 during the Indonesia–Malaysia confrontation The Indonesia–Malaysia confrontation began in early 1963 following Indonesia's opposition to the creation of Malaysia. In December 1964, a build-up of Indonesian forces on the Kalimantan border saw the British government commit significant forces from the UK-based Army Strategic Command and Australia and New Zealand deployed roulement combat forces from West Malaysia to Borneo in 1965–66. In January 1965, the first UK-based units (aside from air defence and special forces) arrived and after six weeks of jungle training, deployed on operations. The 1st Battalion Gordon Highlanders arrived first and became the thirteenth