Indonesia–Malaysia confrontation party which was founded in June 1959. The Sarawak Insurgency began after the Brunei Revolt in 1962 and SCO would fight alongside the Bruneian rebels and Indonesian forces during the Indonesia–Malaysia confrontation (1963–1966). The Sarawak Communist Organisation and the Bruneian rebels supported and propagated the unification of all British Borneo territories to form an independent leftist North Kalimantan state. This idea was originally proposed by A. M. Azahari, leader of the Parti Rakyat Brunei (Brunei People's Party), who had forged links with Sukarno's nationalist movement, together with Ahmad Zaidi, in Java in the 1940s. However, the Brunei People's Party was
Brunei–Malaysia border and Sabah, Malaysia, on the other. All three territories were then ruled by Britain. The powers for the order in council were derived from the British Colonial Boundaries Act of 1895. Brunei and Malaysia still adhere to the British Orders in Council to define their territorial waters, where it was referred to in the Joint Statement made after the 18th Annual Leaders' Consultation between the Sultan of Brunei and Prime Minister of Malaysia on 3 November 2014 when reference was made to the Sarawak (Definition of Boundaries) Order in Council 1958 No 1518 as part of the boundary definition process