Diego Garcia Military Base and British Indian Ocean Territory Bill: Second Reading
330
Ayes
—
179
Noes
Passed · Government won
140 did not vote
Analysis
Commons
Commons
**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.
Voting Aye meant
Support the Chagos Islands treaty and the legislation needed to transfer sovereignty to Mauritius while securing long-term UK military control of Diego Garcia
Voting No meant
Oppose the Chagos Islands deal, arguing the terms are too costly or concede too much sovereignty, or that the strategic and legal risks outweigh the benefits of securing the base
509 voting MPs. Each dot is one vote; left-to-right by party. Grey dots in the centre are the 140 who did not vote.
Aye
No
Absent
Labour PartyWhipped Aye
280
1
81
Conservative and Unionist PartyWhipped No
0
102
14
Liberal DemocratsWhipped No
0
60
12
Labour and Co-operative PartyWhipped Aye
35
0
7
Independent
7
3
3
Scottish National Party
0
0
9
Reform UKWhipped No
0
8
—
Sinn Féin
0
0
7
Democratic Unionist PartyWhipped No
0
5
—
Green Party of England and WalesWhipped Aye
3
0
1
Plaid Cymru
0
0
4
Social Democratic and Labour Party
2
0
—
Alliance Party of Northern Ireland
0
0
1
Speaker
0
0
1
Traditional Unionist Voice
0
1
—
Ulster Unionist Party
0
1
—
Your Party
1
0
—
Defends the treaty as securing critical defence interests against legal threats; claims the previous Conservative government started negotiations for the same reason; attacks Opposition for not publishing their own negotiating position.Labour · Voted aye · Read full speech (6,936 words) →
Opposes the bill as an unjustified surrender of sovereignty, arguing the UK paid for freehold ownership in the 1960s and is now renting back at £35 billion cost; rejects legal threat narrative and argues previous Foreign Secretary Cameron ended negotiations, not left a deal.Conservative · Voted no · Read full speech (5,932 words) →
Questions whether the deal retains rolling sovereignty after 99 years and challenges the government's claimed compensation to Mauritius, asserting Labour has capitulated compared to Conservative negotiating position.Conservative · Voted no · Read full speech (208 words) →
Argues the ICJ judgment was not legally binding on the UK and criticises use of Net Present Value methodology to justify the cost, which conflates commercial accounting with sovereign treaty obligations.Conservative · Voted no · Read full speech (2,780 words) →
Demands a full apology (not just regret) for Chagossian treatment; notes legal judgment supports return to Mauritius; seeks clarity on resettlement rights and Diego Garcia access for displaced islanders.Independent · Voted aye · Read full speech (1,877 words) →
Questions whether the 99-year lease with only first refusal truly secures the base long-term; warns Britain becomes hostage to future Mauritian decisions and risks losing the base in four generations.Conservative · Voted no · Read full speech (3,644 words) →
Challenges the government's costings and accounting methodology, citing disagreement with the Government Actuary's Department and Office for Budget Responsibility; questions why NPV has not been used in comparable government decisions.Conservative · Voted no · Read full speech (406 words) →
Supports the deal; notes US Defence Secretary and President Trump endorsement; questions why Conservatives who negotiated 85% of the treaty now oppose it from opposition benches.Labour · Voted aye · Read full speech (2,131 words) →
Sources
Division dataUK Parliament Votes API
DebateHansard · Commons
Stance analysisAI analysis · Claude 4.x
LicenceOpen Parliament Licence v3.0