Diego Garcia Military Base and British Indian Ocean Territory Bill: motion to disagree with Lords Amendment 6

What happened: The House of Commons voted 347 to 184 to reject Lords Amendment 6 to the Diego Garcia Military Base and British Indian Ocean Territory Bill. The amendment would have introduced an ongoing parliamentary scrutiny mechanism over the financial costs of the treaty with Mauritius governing the future of the Diego Garcia military base in the British Indian Ocean Territory. The government's motion to disagree with the Lords' position passed comfortably, removing this oversight provision from the Bill.

Why it matters: The vote was part of a broader effort to pass the Bill enabling a treaty with Mauritius under which the UK retains operational control of the Diego Garcia base for 99 years in exchange for financial payments and the cession of sovereignty over the Chagos Islands to Mauritius. Lords Amendment 6 sought to embed a formal estimates and supply scrutiny process for the payments made under the treaty, adding a layer of ongoing parliamentary accountability for the deal's costs over its near-century lifespan. By voting it down, the Commons maintained the government's position that existing financial transparency measures, including published payment schedules, verification by the Government Actuary's Department, and assessments from the Office for Budget Responsibility, are sufficient. The vote took place on the same day as closely related votes rejecting Lords Amendment 5 (on publishing real-terms cost information) and Lords Amendment 1, all by similar margins.

The politics: The vote split almost entirely along government-versus-opposition lines. Labour and Labour and Co-operative MPs voted overwhelmingly in favour, while Conservatives, Liberal Democrats, Reform UK, Democratic Unionist Party, Plaid Cymru, and Traditional Unionist Voice MPs voted against. Two Labour MPs broke with their party to vote no. Three Green MPs backed the government. The debate was overshadowed by President Trump's publicly stated opposition to the deal the previous night, which Conservative MPs used repeatedly to challenge the government's insistence that key allies supported the agreement. The government argued that previous US endorsements remained the relevant position and that discussions with the new US administration were ongoing.