Opposition Day: British Indian Ocean Territory

What happened

On 28 January 2026, the House of Commons voted on an Opposition Day motion -- a debate and vote initiated by the Conservative opposition -- opposing the government's handling of the British Indian Ocean Territory (BIOT). The motion called on Parliament to reject the ceding of sovereignty over BIOT to Mauritius, opposed the proposed £34.7 billion payment to Mauritius, and argued that the government's approach breached a 1966 defence agreement with the United States. The motion was defeated by 284 votes to 103.

Why it matters

The vote concerns the future of Diego Garcia, a strategically vital military base in the Indian Ocean used jointly by the UK and the United States. The government has been pursuing a deal to transfer sovereignty of the Chagos Islands -- which form part of BIOT -- to Mauritius, subject to an agreement that would allow the base to continue operating. Critics argue this arrangement would cost the British taxpayer £34.7 billion, compromise national security, and undermine the UK's treaty obligations to the United States. The government's position, reflected in the No vote, is that its approach to BIOT is legally sound and in the UK's strategic interest.

The politics

The vote divided almost entirely along party lines. All 279 Labour and Labour Co-operative MPs who voted backed the government, while 96 of the 116 voting Conservatives supported the motion, joined by five Reform UK MPs, two Democratic Unionist Party MPs, one Traditional Unionist Voice MP, and one independent. The SNP abstained entirely. The debate sits within a broader and ongoing legislative fight over the Diego Garcia Military Base and British Indian Ocean Territory Bill, which the Lords had sought to amend, only for the Commons to disagree with those amendments in votes held just eight days earlier on 20 January 2026.