Unfederated Malay States in the context of "Fall of Singapore"

The term British Malaya (/məˈleɪə/; Malay: Tanah Melayu British) loosely describes a set of states on the Malay Peninsula and the island of Singapore that were brought under British hegemony or control between the late 18th and the mid-20th century. Unlike the term "British India", which excludes the Indian princely states, British Malaya is often used to refer to the Federated and the Unfederated Malay States, which were British protectorates with their own local rulers, as well as the Straits Settlements, which were under the sovereignty and direct rule of the British Crown, after a period of control by the East India Company.

Before the formation of the Malayan Union in 1946, the territories were not placed under a single unified administration, with the exception of the immediate post-war period when a British military officer became the temporary administrator of Malaya. Instead, British Malaya comprised the Straits Settlements, the Federated Malay States, and the Unfederated Malay States. Under British hegemony, Malaya was one of the most profitable territories of the empire, being the world's largest producer of tin and later rubber. During the Second World War, Japan ruled a part of Malaya as a single unit from Singapore.

The Anglo-Siamese Treaty of 1909, also known as the Bangkok Treaty of 1909, was an agreement between the United Kingdom and the Kingdom of Siam (now Thailand). It was signed on 10 March 1909 in Bangkok, with ratifications exchanged in London on 9 July 1909. The treaty established the modern border between Malaysia and Thailand. Areas around modern Pattani, Narathiwat, southern Songkhla, Satun and Yala remained under Thai control, later becoming the site of the South Thailand insurgency.

Under the treaty, Thailand relinquished claims to Kedah (Thai: ไทรบุรี, romanized: Saiburi), Kelantan (กลันตัน, Kalantan), Perlis (ปะลิส, Palit) and Terengganu (ตรังกานู, Trangkanu), which entered the British sphere of influence as protectorates. During World War II, Thailand briefly reclaimed these territories with Japanese permission, but they were returned to British control after the defeat of the Axis powers. These four states, together with Johor, later became known as the Unfederated Malay States, eventually joining the Federation of Malaya and forming part of present-day Malaysia.

The Federated Malay States (FMS, Malay: Negeri-Negeri Melayu Bersekutu, Jawi: نݢري٢ ملايو برسکوتو) was a federation of four integrated protectorates in the Malay Peninsula comprising Selangor, Perak, Negeri Sembilan and Pahang. It was established in 1895 by the British government and lasted until 1946. In that year, these states joined with two of the former Straits Settlements (Malacca and Penang, excluding Singapore) and the Unfederated Malay States to form the Malayan Union. The union was short-lived and in 1948 was replaced by the Federation of Malaya, which gained independence in 1957. This federation later became Malaysia in 1963 following the inclusion of North Borneo (now Sabah), Sarawak and Singapore. Singapore was eventually separated from Malaysia and became a sovereign state on 9 August 1965.

Unlike the Unfederated Malay States, which retained greater internal autonomy, the real authority in the FMS resided with the four British Residents and the Resident-General. The powers of the local rulers were significantly restricted and were largely confined to matters "touching Malay religion and customs". The administration of the FMS represented a more centralised and interventionist colonial governance model in contrast to the comparatively decentralised arrangements in the Unfederated States. Nevertheless, the FMS remained nominally more autonomous than the Straits Settlements, which were directly governed by Britain through its Governor.