Diego Garcia Military Base and British Indian Ocean Territory Bill: motion to disagree with Lords Amendment 5
347Ayes
185Noes
Carried · majority 162 · Government won113 did not vote
645 Members · Aye 347 · No 185 · DNV 113 · grey dots in centre are abstentions
Analysis
Commons
Commons
Commons MPs voted 347 to 185 on 20 January 2026 to reject Lords Amendment 5 to the Diego Garcia Military Base and British Indian Ocean Territory Bill. The amendment would have required the Secretary of State to publish the total real-terms cost of payments made to Mauritius under the Chagos treaty, including the methodology used by the Government Actuary's Department and the Treasury to calculate them. By voting to disagree with the Lords, the Commons removed this transparency requirement from the Bill. The practical effect is that the government will not face a statutory duty to publish a full real-terms cost breakdown of the payments to Mauritius. The government argued that this information was already publicly available, pointing to the financial exchange of letters and the explanatory memorandum published on the day the treaty was signed, which it said set out the payment schedule and the methodology using Office for Budget Responsibility forecast inflation figures. Opponents argued that without a legal obligation, the published figures remain incomplete and that the government had been actively understating the true cost to taxpayers, contrasting a government figure of around 3.5 billion pounds with a figure attributed to the Government Actuary's Department of 35 billion pounds. The vote split almost entirely along party lines. All 336 Labour and Labour-Co-operative MPs who voted supported the government's motion to reject the amendment. Every Conservative, Liberal Democrat, Reform UK, DUP and Plaid Cymru MP who voted opposed it. Three Green MPs voted with the government, as did six independents and two members listed as Your Party. The division followed the same pattern as three other votes held the same day on related Lords amendments to the same Bill, all of which the government also won by similar margins.
Voting Aye meant
Support rejecting the Lords amendment, accepting that existing published financial disclosures are sufficient and that demanding further transparency requirements is unnecessary
Voting No meant
Support the Lords amendment, insisting the government must be legally required to publish full real-terms costs and methodology — arguing the current figures mislead taxpayers about the true scale of the deal
Each row is one party. The stacked bar gives the within-party split of Aye / No / Absent; the columns on the right give the raw counts. The whip column shows the published party position — “Free vote” means the whip was formally removed for this division.
Party
Whip
Aye / No / Abs
Aye
No
Abs
Labour Party
Whipped Aye
299
2
60
Conservative and Unionist Party
Whipped No
0
100
16
Liberal Democrats
Whipped No
0
64
7
Labour and Co-operative Party
Whipped Aye
37
0
5
Independent
—
6
3
4
Scottish National Party
—
0
0
9
Reform UK
Whipped No
0
7
1
Sinn Féin
—
0
0
7
Democratic Unionist Party
Whipped No
0
5
0
Green Party of England and Wales
Whipped Aye
3
0
1
Plaid Cymru
Whipped No
0
4
0
Social Democratic and Labour Party
—
1
0
1
Your Party
—
2
0
0
Alliance Party of Northern Ireland
—
0
0
1
Restore Britain
—
0
1
0
Speaker
—
0
0
1
Traditional Unionist Voice
—
0
1
0
Ulster Unionist Party
—
0
1
0
Source · Hansard · UK Parliament Votes API · whip status from announced positions; “free vote” indicates the whip was formally removed
As government minister, defended the treaty as vital to national security, emphasizing the base's protection for 99 years, robust safeguards against adversaries, and backing from allies including the US despite Trump's morning criticism; rejected Lords amendments as unnecessary or politically motivated.Labour · Voted aye · Read full speech (7,050 words) →
Led opposition arguing the deal surrenders British sovereignty for £35 billion with no credible reason, especially after President Trump explicitly rejected it; called for withdrawal of the Bill and demanded transparency on costs and protection of Chagossian self-determination rights.Conservative · Voted no · Read full speech (2,310 words) →
Challenged the government's reliance on US support by pointing out Trump's public rejection of the deal that morning; questioned how the government can justify proceeding without addressing fundamental changes in the US position.Conservative · Voted no · Read full speech (388 words) →
Argued the legal justifications (ICJ judgment, UNCLOS, ITU) had fallen apart under scrutiny; criticised the government for rushing through legislation despite lack of compelling reasons and demanded a pause to consult the now-sceptical US Administration.Conservative · Voted no · Read full speech (1,316 words) →
Supported Lords amendments on cost transparency, environmental durability, and Chagossian self-determination; argued the amendments provide legitimate safeguards and called for government pause given changing geopolitical circumstances, particularly US position shift.Liberal Democrat · Voted no · Read full speech (1,368 words) →
Expressed concern that paying for something the UK owns lacks rationale; called for referendum on Chagossian return rather than surveys, and urged pause to comply with UN Committee on the Elimination of Racial Discrimination and respond to US position change.Labour · Voted no · Read full speech (837 words) →
Defended the treaty as securing critical military assets for 99 years with full operational freedom; argued Lords amendments are unnecessary as international law and joint commissions already address contingencies; rejected claims that social media posts should drive long-term security decisions.Labour · Voted aye · Read full speech (1,255 words) →
Suggested material changes in circumstances (Trump's stance) warrant pausing implementation; implied the previous Conservative Government would never have accepted such a deal given current US opposition.Conservative · Voted no · Read full speech (92 words) →
Sources
Division dataUK Parliament Votes API
DebateHansard · Commons
Stance analysisAI analysis · Claude 4.x
LicenceOpen Parliament Licence v3.0