Bashfield, Samuel2024-09-232024-09-23https://hdl.handle.net/1885/733720786While Britain decolonised its global empire in the post-Second World War period, one more colony was mysteriously, surreptitiously and illegally created in 1965 - the British Indian Ocean Territory (BIOT). Ostensibly, BIOT was created to house a humble Anglo/US military communications station on the largest island of Diego Garcia, strategically located in the centre of the Indian Ocean. However, BIOT's strategic utility went far beyond secure military communications. Put simply, BIOT was created to facilitate a Cold War transfer of hegemonic power from the United Kingdom to the United States, and to perpetuate Western power in the Indian Ocean Region and Middle East. This historical dissertation examines British and American interests in BIOT between 1965 and the Cold War's end. Its chapters illuminate how respective Anglo-US defence strategies shaped BIOT's militarisation, how BIOT was used to slow Britain's withdrawal 'East of Suez,' how Britain used BIOT to entrench the US in the Indian Ocean, how Britain used BIOT to attain discounted submarine-launched ballistic missiles across three separate deals, and lastly, how dissenting regional states were rebuffed. Diego Garcia did not become one of the West's most critical overseas bases haphazardly but was painstakingly selected and cultivated throughout the Cold War as a linchpin of Western predominance, no matter the considerable political costs. Using recently declassified American, British and Australian archives, this project sheds light on how BIOT was selected, militarised, transacted and defended from its creation through to the Cold War's end.en-AU202510.25911/ZEW6-5B59