The Diego Garcia Bill, formally known as the Diego Garcia Military Base and British Indian Ocean Territory Bill, has returned to the House of Commons for critical consideration of amendments proposed by the House of Lords. This legislative milestone comes amid heightened controversy surrounding the UK's agreement to cede sovereignty of the Chagos Islands to Mauritius while securing a long-term lease for the strategically vital Diego Garcia military base. As of January 20, 2026, Members of Parliament (MPs) are debating whether to accept, reject, or amend the Lords' changes, marking a pivotal 'ping-pong' stage in the parliamentary process. The bill's progression underscores deep divisions over national security, historical injustices against the Chagossian people, and geopolitical implications in the Indian Ocean region.

Originally introduced in late 2025, the legislation aims to implement a treaty signed between the UK and Mauritius in October 2024. Under the deal, the UK relinquishes sovereignty over the British Indian Ocean Territory (BIOT), comprising the Chagos Archipelago, but retains operational control of Diego Garcia—home to a joint UK-US military installation—through a 99-year lease. Payments to Mauritius are set at £100 million upfront plus £65 million annually, adjusted for inflation. Proponents argue this resolves a long-standing colonial dispute validated by international rulings, while critics warn it exposes the base to future risks from Mauritius' shifting alliances, particularly with China.

The return to the Commons follows intense scrutiny in the upper house. On January 5, Lords voted on amendments during report stage, and by January 12, the bill passed third reading alongside a non-binding regret motion expressing unease over the deal. Key amendments sought protections for Chagossian resettlement rights, environmental safeguards for the pristine Chagos Marine Protected Area, and guarantees against foreign influence on the base. Government ministers have signaled intent to overturn most changes, prioritizing swift enactment to honor the treaty.

Historical Context of the Chagos Islands Dispute

The roots of the Diego Garcia Bill trace back to the mid-20th century. In 1965, the UK detached the Chagos Archipelago from Mauritius—then a colony—to form the British Indian Ocean Territory (BIOT). This move facilitated the construction of a US military base on Diego Garcia, the largest island, which became operational in the 1970s. Between 1967 and 1973, around 1,500-2,000 Chagossians, primarily of African and Indian descent, were forcibly evicted to Mauritius and Seychelles to make way for the base. Described by some as 'one of the worst crimes of the last century,' the exiles received minimal compensation and have campaigned for decades for the right of return.

International pressure mounted over time. The UN General Assembly voted repeatedly for UK withdrawal, and in 2019, the International Court of Justice (ICJ) issued an advisory opinion declaring the detachment unlawful and BIOT's creation a violation of self-determination. The International Tribunal for the Law of the Sea echoed this in 2021. Domestically, the UK Supreme Court ruled in 2021 that Chagossians have a case for compensation. These developments pressured successive UK governments, culminating in the 2024 treaty under then-Prime Minister Rishi Sunak.

The agreement allocates ¤0 million per year for Chagossian support via Mauritius, plus a potential resettlement feasibility study on outer islands (excluding Diego Garcia). However, critics like former MP Andrew Rosindell argue it abandons Chagossian claims without direct negotiation, effectively endorsing their exile.

Parliamentary Journey: From Commons to Lords and Back

The bill cleared its second reading in the Commons in December 2025 with government majority support. It then faced robust opposition in the Lords, where crossbenchers and Conservatives tabled amendments. During report stage on January 5, peers debated security clauses ensuring perpetual UK-US access regardless of Mauritius' government. A January 10 article highlighted rare interventions by senior military figures warning of 'horrific' implications for Diego Garcia.

Third reading on January 12 saw a regret motion pass, signaling unease but not blocking progress. Lords amendments included mandates for Chagossian consultation, environmental impact assessments, and safeguards against base lease revocation. The government's rushed scheduling—third reading just two days after report—drew accusations of guillotining debate, as noted by Rosindell on social media.

Now in the Commons, ministers like Dan Jarvis defend the bill as essential for defense imperatives. MPs must vote on each amendment in a process that could extend into late January 2026. If disagreements persist, further ping-pong ensues until resolution or bill failure—unlikely given Labour's majority.

Key Lords Amendments Under Scrutiny

Several amendments stand out:

• Chagossian Rights: Requires direct negotiations with exiled communities before sovereignty transfer, addressing claims of inadequate representation.
• Environmental Protections: Mandates upholding the Chagos Marine Protected Area, one of the world's largest, against potential fishing or development by Mauritius.
• Security Guarantees: Inserts clauses preventing Mauritius from granting base access to adversaries like China, amid Mauritius' neutral foreign policy.
• Resettlement Feasibility: Compels a binding study on outer islands habitability, beyond the treaty's voluntary commitment.

Conservative peer Zac Goldsmith hailed Lords rejection as a victory, urging the government to concede for security and environmental reasons. Chagossian Voices advocates retaining amendments to prevent 'new colonialism.'

Donald Trump's Intervention and Global Repercussions

US President Donald Trump's January 20 criticism amplified the debate, labeling the handover 'an act of great stupidity' and linking it to his Greenland acquisition push. Trump argued it weakens US-UK strategic assets, echoing concerns from figures like Nile Gardiner. BBC live updates noted Mauritius' response: sovereignty 'no longer up for debate.'

The base supports US operations in the Middle East, Asia-Pacific, and beyond—bombers, submarines, intelligence. Analysts warn Chinese influence via Mauritius could jeopardize this, given Beijing's Indian Ocean port investments. Sky News highlighted UK firmness despite backlash.

Guardian explainer contextualized Chagos within decolonization, but US reservations add transatlantic tension. UK officials reassure the lease is ironclad, with termination penalties exceeding £billions.

Stakeholder Perspectives: A Divided Landscape

Government View: Foreign Secretary David Lammy frames the deal as 'decolonization with safeguards,' resolving legal vulnerabilities exposed by ICJ. It averts UN sanctions and secures the base long-term.

Opposition: Conservatives like Goldsmith and Rosindell decry it as breaching manifesto pledges to retain sovereignty. Labour rebels and crossbenchers echo security fears.

Military Experts: Retired officers in Conservative Post warn of geo-strategic crisis, citing Mauritius' 2024 election of China-friendly elements.

Chagossians: Split—some welcome compensation, others via groups like Chagossian Voices demand veto rights.

Environmentalists: Praise MPA but fear dilution; Catherine McBride OBE urged Lords rejection for ecosystem preservation.

Strategic and Security Implications

Diego Garcia's atoll location enables rapid power projection—400m runway, prepositioned supplies. Post-9/11, it supported Afghan, Iraq wars; today, counters China in Indo-Pacific.

Risks include:

• Mauritius revocation post-99 years or via politics.
• China's 'String of Pearls' encircling India.
• Legal challenges undermining lease.

Proponents cite treaty's 'no termination' clause and UK veto on outer islands. Yet, Telegraph columnist Graham Stringer called it a 'grave injustice' breaching pledges. Dan Boucher argued it endangers US-UK defense.

Alternatives floated: Direct Chagossian sovereignty or perpetual UK control, but international law constrains.

Humanitarian and Economic Dimensions

Chagossians, numbering 10,000+ descendants, live in poverty despite £40m UK payouts since 1980s. The bill channels funds via Mauritius, raising mismanagement fears. Resettlement trials (2000s) failed due to costs (£400m+), logistics.

Economically, Mauritius gains legitimacy, revenue; UK avoids £100m+ annual legal fees. BIOT fishing licenses previously netted millions.

Commons Library briefing details fiscal impacts, urging scrutiny.

Future Outlook and Potential Outcomes

If Commons rejects amendments, royal assent follows, transfer by mid-2026. Ping-pong could delay to February. Failure unlikely, but revolt possible amid Trump pressure.

Long-term: Base endures, but monitors Mauritius elections (next 2029). Chagossian lawsuits loom; environmental NGO challenges anticipated.

Broader: Sets decolonization precedent for Falklands, Gibraltar. Strengthens UK-Mauritius ties, but strains US relations temporarily.

For observers, this tests parliamentary sovereignty versus executive treaty powers. As debates unfold, security trumps history—or vice versa?

Photo by Jose Manuel Esp on Unsplash

What This Means for the UK Public

Beyond geopolitics, the bill affects taxpayer value: Lease costs vs. retained control. Public sentiment on X reflects polarization—security hawks vs. justice advocates.

Actionable insights: Follow Parliament TV for Commons sessions; engage MPs via contact resources. For career impacts in defense policy, explore higher-ed jobs in international relations.

In summary, the Diego Garcia Bill's return to the Commons crystallizes a complex interplay of history, strategy, and law. Resolution imminent, legacy enduring.