Diego Garcia Military Base and British Indian Ocean Territory Bill — Amendment Paper: HL Bill 139-R Running list of amendments - 22 December 2025

Diego Garcia Military Base and British Indian Ocean
Territory Bill
RUNNING LIST OF ALL
AMENDMENTS ON REPORT
Tabled up to and including
22 December 2025
[Amendments marked ★ are new or have been altered]
Clause 1
LORD CRAIG OF RADLEY
LORD HOUGHTON OF RICHMOND
_ Clause 1, page 1, line 7, at end insert “, subject to subsection (2A).
(2A) Sections 2 to 4 of this Act come into force only when the Secretary of State has
sought to negotiate an amendment to Article 11 of the Treaty to ensure that the
United Kingdom would cease to make payments to the government of Mauritius
in the event that the use of the Base for military purposes became impossible.”
Member's explanatory statement
This amendment seeks to ensure that, before the ratification of the Treaty, His Majesty's
Government makes arrangements for the terms of payment should environmental or other issues
make the military use of the Base permanently impossible.
LORD CALLANAN
_ Clause 1, page 1, line 7, at end insert “, subject to subsection (2A).
(2A) Section 3 comes into force only when the Secretary of State has undertaken a
consultation of the Chagossian community and laid a report of that consultation
before both Houses of Parliament.”
Member's explanatory statement
This amendment would prevent the provisions of this Bill relating to citizenship from coming into
force unless the Secretary of State has undertaken a consultation of the Chagossian community.
59/1 HL Bill 139—R—Running List 22 December

LORD CALLANAN
_ Clause 1, page 1, line 7, at end insert “, subject to subsection (2A).
(2A) Sections 2 to 4 of this Act come into force only when the duties outlined in section
(Chagos marine protected area) have been discharged.”
Member's explanatory statement
This amendment would prevent the provisions from coming into force until the Government has
published its plan to ensure the long-term protection of the Chagos Marine Protected Area.
LORD CALLANAN
_ Clause 1, page 1, line 7, at end insert “, subject to subsection (2A).
(2A) Sections 2 to 4 of this Act come into force only when the Secretary of State has—
(a) sought to undertake negotiations with the government of Mauritius on
whether Mauritius will establish a right for Chagossians to return and
reside in the Chagos Islands, and
(b) laid before both Houses of Parliament a report on progress on establishing
negotiations with the government of Mauritius and the outcome of any
that take place.
(2B) Within two months of the report being laid before the House of Parliament under
subsection (2A)(b) the Secretary of State must arrange for substantive motions to
be tabled in both Houses of Parliament on the contents of the report.
(2C) In subsection (2A), “Chagossians” are defined as those eligible for British
Citizenship under clause 4 of the Treaty and their descendants.”
Member's explanatory statement
This amendment requires that the Government must undertake negotiations with Mauritius on
a Chagossian right of return, with a report laid before Parliament on the outcome of the negotiations.
The Government must subsequently table a substantive motion in the House of Commons on the
content of that report.
LORD CALLANAN
_ Clause 1, page 1, line 7, at end insert “, subject to subsection (2A).
(2A) Sections 2 to 4 of this Act come into force only when the Secretary of State has—
(a) sought to undertake negotiations with the government of Mauritius to
guarantee that Annex 2.3 will oblige (where the UK Government requests)
the Mauritian government to take responsibility for all asylum claimants
and illegal entrants in the Chagos Archipelago including Diego Garcia
and accept the transfer of all claimants to Mauritian custody, and
(b) laid before both Houses of Parliament a report on progress on establishing
negotiations with the government of Mauritius and the outcome of any
that take place.
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(2B) Within two months of the report being laid before the Houses of Parliament under
subsection (2A)(b), the Secretary of State must arrange for substantive motions to
be tabled in both Houses of Parliament on the contents of the report.”
Member's explanatory statement
This amendment would prevent the UK being responsible for asylum claims resulting from illegal
entrants into the Chagos Archipelago.
LORD CALLANAN
_ Clause 1, page 1, line 7, at end insert “, subject to subsection (2A).
(2A) Sections 2 to 4 of this Act come into force only when the Secretary of State has—
(a) sought to negotiate guarantees from the government of Mauritius that the
United Kingdom will have the right to renew the lease at the end of the
99-year period in Article 13 of the Treaty and any subsequent period at
the same or more favourable terms, and
(b) laid before both Houses of Parliament a report on the progress of the
negotiations to seek guarantees from Mauritius.
(2B) Within two months of the report being laid before the House of Parliament under
subsection (2A)(b), the Secretary of State must arrange for substantive motions to
be tabled in both Houses of Parliament on the contents of the report.”
Member's explanatory statement
This amendment would prevent the Treaty from coming into force until the Government sought
guarantees from the Mauritian government that the lease is renewable as of right.
LORD CALLANAN
_ Clause 1, page 1, line 7, at end insert “, subject to subsection (2A).
(2A) Sections 2 to 4 of this Act come into force only when the duties outlined in section
(Cost of the Treaty) have been discharged.”
LORD CALLANAN
_ Clause 1, page 1, line 7, at end insert “, subject to subsection (2A).
(2A) Sections 2 to 4 of this Act come into force only when the Secretary of State has
published a statement setting out that the Secretary of State is satisfied that—
(a) the government of Mauritius is not unduly influenced by hostile state
actors, and
(b) there will be no interference by hostile state actors in the operation of the
base.”
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LORD CALLANAN
_ Clause 1, page 1, line 7, at end insert “, subject to subsection (2A).
(2A) Sections 2 to 4 of this Act come into force only when the duties outlined in section
(UN CERD Report on the UK-Mauritius Agreement) have been discharged.”
LORD LILLEY
★ _ Clause 1, page 1, line 7, at end insert “, subject to subsection (2A).
(2A) Sections 2 to 4 of this Act come into force only when either the International Court
of Justice or the International Tribunal for the Law of the Sea has delivered binding
and enforceable judgements on the sovereignty of the Chagos Archipelago and
judged that the islands should be transferred to Mauritius.”
Member's explanatory statement
This amendment would only allow sections 2 to 4 to come into force if an international Court
delivers a binding ruling on sovereignty of the Chagos Archipelago and directs that they should
be transferred to Mauritius.
LORD LILLEY
★ _ Clause 1, page 1, line 7, at end insert “, subject to subsection (2A).
(2A) Sections 2 to 4 of this Act come into force only when the Secretary of State has
negotiated guarantees from the government of Mauritius that Mauritius accepts
all and any liability for future reparations awarded to the Chagossian people as
a result of their expulsion from the islands.”
LORD LILLEY
★ _ Clause 1, page 1, line 7, at end insert “, subject to subsection (2A).
(2A) Sections 2 to 4 of this Act come into force only when the Secretary of State has
replied in full to the House of Lords International Relations and Defence
Committee report of 17th December titled “Chagossian views on the Agreement
with Mauritius concerning the Chagos Archipelago”.”
LORD LILLEY
★ _ Clause 1, page 1, line 7, at end insert “, subject to subsection (2A).
(2A) Sections 2 to 4 of this Act come into force only once all outstanding legal actions,
including appeals, by the Chagossian people have been determined.”
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LORD LILLEY
★ _ Clause 1, page 1, line 7, at end insert “, subject to subsection (2A).
(2A) Sections 2 to 4 of this Act come into force only when the Secretary of State has
sought to negotiate guarantees from the government of Mauritius that Mauritius
will not enforce its duties under the Pelindaba Treaty on the base at Diego Garcia
and if they were to do so the sovereignty of the base would revert to the UK.”
Member's explanatory statement
This amendment seeks to expand on the Minister's statements in Committee that the Treaty of
Pelindaba will not be enforced by Mauritius on the UK and US base.
After Clause 1
BARONESS FOSTER OF AGHADRUMSEE
_ After Clause 1, insert the following new Clause—
“Referendum
(1) The Secretary of State must arrange a referendum on whether the British Indian
Ocean Territory should—
(a) remain a British Overseas Territory, or
(b) be transferred to and become the sovereign territory of the Republic of
Mauritius.
(2) No transfer of sovereignty may take place under section 2 unless the number of
Chagossians voting to transfer the islands to Mauritius exceeds those of the
Chagossians that wish to remain a British Overseas Territory.
(3) The franchise for the referendum must consist of persons entitled to citizenship
under section 4 who are over 18 years of age, wherever they are resident.
(4) The Secretary of State must ensure that eligible persons resident outside the United
Kingdom are able to participate in the referendum.
(5) The Secretary of State must lay before Parliament a statement of the result of the
referendum as soon as reasonably practicable after it has been held.”
Clause 5
LORD LANSLEY
_ Clause 5, page 3, line 39, at end insert—
“(2A) An Order under this section which amends, repeals or revokes an Act may not
be made unless a draft of the instrument has been laid before and approved by a
resolution of each House of Parliament.”
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LORD LANSLEY
_ Clause 5, page 3, line 40, leave out “An” and insert “Any other”
LORD LANSLEY
_ Clause 5, page 3, line 41, leave out from “Parliament” to end of line 3 on page 4
LORD LANSLEY
_ Clause 5, page 4, line 12, leave out paragraph (b)
After Clause 5
LORD CRAIG OF RADLEY
LORD HOUGHTON OF RICHMOND
_ After Clause 5, insert the following new Clause—
“Statement: base usability
The Secretary of State must publish a statement before the ratification of the Treaty
setting out how they would respond should the Base become unusable and the
impact that this would have on the operation of the Treaty.”
LORD CALLANAN
_ After Clause 5, insert the following new Clause—
“Article 11: schedule of payments to Mauritius
Within one month of the day on which this Act is passed, Secretary of State must
publish a schedule of expected payments to Mauritius under Article 11 of the
Treaty, including the planned dates of each payment.”
Member's explanatory statement
This amendment would require the Secretary of State to publish a schedule of expected payments
to Mauritius under Article 11 of the Treaty.
LORD CALLANAN
_ After Clause 5, insert the following new Clause—
“Article 15: termination of the Treaty
Within one month of the day on which this Act is passed, the Secretary of State
must publish a statement setting out their understanding of the status of the
Chagos Archipelago should the Treaty be terminated.”
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Member's explanatory statement
This amendment would require the Secretary of State to publish a statement of the Government’s
understanding of the legal status of the Chagos Archipelago should the Agreement be terminated.
LORD CALLANAN
_ After Clause 5, insert the following new Clause—
“Resettlement of Chagossians
Within one month of the day on which this Act is passed, the Secretary of State
must undertake a review of all discussions between the UK and Mauritius in
respect of the resettlement of the Chagossians under Article 6 of the Treaty and
publish a report of the findings of the review.”
Member's explanatory statement
This amendment would require the Secretary of State to review the records of all negotiations
between the UK and Mauritius in respect of Article 6 of the agreement and publish the findings
of the review.
LORD CALLANAN
_ After Clause 5, insert the following new Clause—
“Article 5: support and assistance
Within one month of the day on which this Act is passed, the Secretary of State
must publish an estimate of the ongoing financial cost of providing support and
assistance to Mauritius under Article 5 of the Treaty.”
Member's explanatory statement
This amendment would require the Secretary of State to publish an estimate of ongoing financial
cost of providing support and assistance to Mauritius under Article 5 of the agreement.
LORD CALLANAN
_ After Clause 5, insert the following new Clause—
“Chagos marine protected area
The Secretary of State must publish a report stating how they intend to preserve,
in perpetuity, the Chagos Marine Protected Area, under Article 5 of the Treaty,
including steps to ensure—
(a) the provision of Mauritian fishing protection vessels providing the same,
or better, prevention of illegal fishing than the BIOT patrol,
(b) that Mauritius commits to retaining the Chagos Marine Protected Area as
a no-catch zone, and
(c) the prevention of litter, waste, debris or pollution within the Chagos Marine
Protected Area.”
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LORD CALLANAN
_ After Clause 5, insert the following new Clause—
“Notification of Mauritius under paragraph 3(b) of Annex 1
(1) His Majesty’s Government may not notify Mauritius of the location of equipment
in the Chagos Archipelago beyond Diego Garcia before conducting maintenance
and upgrades.
(2) The duty in subsection (1) applies to all members and representatives of His
Majesty’s Government and all Ministers of the Crown.”
Member's explanatory statement
This amendment seeks to ensure that the Government is not able to endanger UK or USA security
by notifying Mauritius of the location of sensitive defence equipment.
LORD CALLANAN
_ After Clause 5, insert the following new Clause—
“Chagossian Trust Fund Management Board
The Secretary of State must ensure that no person who—
(a) is a member of the government of Mauritius,
(b) has financial links to the government of Mauritius, or
(c) has previously been employed, or is currently employed, by the
government of Mauritius,
may serve as one of the seven Chagossians on the Trust Fund Management Board.”
Member's explanatory statement
This amendment seeks to ensure that the Chagossians on the Trust Fund Management Board do
not have a financial relationship with the Mauritian government.
LORD CALLANAN
_ After Clause 5, insert the following new Clause—
Trust fund
(1) The Secretary of State must seek to negotiate with the government of Mauritius
that the Trust Fund under Article 11(1)(b) of the Treaty will be open to all
Chagossians whether they are also Mauritian or not and will include representation
of all Chagossians in its administration.
(2) The Secretary of State must lay a report on any such negotiations before both
Houses of Parliament and a Minister must seek the approval of both Houses of
the report.
(3) The approval required by subsection (2) must be in the form of a resolution of
each House of Parliament.
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(4) For the purposes of section 1(2), the duties under this section are only discharged
if both Houses of Parliament agree the resolution in subsection (3) of this section.”
LORD CALLANAN
_ After Clause 5, insert the following new Clause—
“Cost of the Treaty
The Secretary of State must publish a statement setting out—
(a) the total real terms cost of payments to be made to Mauritius under the
Treaty;
(b) the full methodology and justification of the discount mechanism used to
calculate the total cost;
(c) the methodology used to calculate the total cost of the Treaty by—
(i) the Office for Budget Responsibility,
(ii) the Government Actuary’s Department, and
(iii) the Treasury.”
LORD CALLANAN
_ After Clause 5, insert the following new Clause—
“UN CERD Report on the UK-Mauritius Agreement
The Secretary of State must publish a statement setting out—
(a) the assessment ministers have made of the impact of the advisory opinion
of the UN Committee on the Elimination of Racial Discrimination in their
report of 8 December 2025 on the legal status of the Diego Garcia Military
Base, and
(b) the steps ministers have taken to engage with the Mauritian government
to address the concerns expressed by the UN Committee on the Elimination
of Racial Discrimination in relation to the legal status of the Diego Garcia
Military Base in their report of 8 December 2025.”
Member's explanatory statement
This amendment would require the Secretary of State to engage with the Mauritian government
to address the concerns expressed by the UN Committee on the Elimination of Racial Discrimination
in their report of 8 December 2025 and publish an official assessment of the impact of the report
on the legal status of the Diego Garcia Military Base.
Clause 6
LORD CALLANAN
_ Clause 6, page 4, line 17, after “1(2)” insert “ and (2A)”
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Diego Garcia Military Base and British Indian Ocean
Territory Bill
RUNNING LIST OF ALL
AMENDMENTS ON REPORT
Tabled up to and including
22 December 2025
22 December 2025
PUBLISHED BY AUTHORITY OF THE HOUSE OF LORDS
59/1 HL Bill 139—R—Running List 22 December