Diego Garcia Military Base and British Indian Ocean Territory Bill: Second Reading

What happened: Parliament voted on 9 September 2025 to pass the Second Reading of the Diego Garcia Military Base and British Indian Ocean Territory Bill, approving the legislation in principle by 330 votes to 179. Second Reading is the stage at which the House of Commons debates and votes on the general principles of a bill, before it proceeds to detailed scrutiny. The government secured a comfortable majority of 151 votes.

Why it matters: The bill concerns the future legal and territorial arrangements for Diego Garcia, the strategically significant atoll in the Indian Ocean that hosts a major joint UK-US military base. By passing Second Reading, the Commons gave the go-ahead for the government to legislate on how the base will be governed and what arrangements will apply to the British Indian Ocean Territory more broadly. The base is a critical asset for both British and American military operations across the Indo-Pacific and beyond, and the legislation addresses how sovereignty and operational rights are structured going forward.

The politics: The vote followed sharply partisan lines. Labour and Labour-Co-operative MPs delivered the vast majority of Aye votes, with only one Labour defection. Conservatives, Liberal Democrats, Reform UK, and the Democratic Unionist Party all voted against, reflecting a broad opposition bloc united in opposing the government's approach rather than any single alternative position. Notably, the three Green MPs and both SDLP members voted with the government, providing a small measure of cross-party support. Subsequent committee-stage votes in October 2025 show the government continued to see off opposition amendments, indicating that while opponents of the bill sought to reshape it at later stages, the government retained firm control of its passage.