Prime Minister Andy Burnham has pledged to work with Mauritius and the United States to find a resolution over the future of the strategically important military base on Diego Garcia.
The commitment follows the failure of legislation intended to implement the UK's Chagos Islands agreement with Mauritius to complete its passage through Parliament.
Downing Street confirmed that Burnham spoke to Mauritian Prime Minister Navin Ramgoolam on 21 September and underlined his commitment to finding a way forward which secures the operation of the base and protects British national security.
Burnham has not announced a replacement agreement or confirmed that the existing treaty will be abandoned. He acknowledged separately that no resolution has yet been reached.
Burnham promises to work towards agreement
Speaking to reporters while travelling to New York for the United Nations General Assembly, Burnham said his assurance to Ramgoolam was that he would work towards a resolution.
He said Britain remained determined to secure the long-term operation of the Diego Garcia base, describing it as crucial to the security of the UK and its allies.
The Prime Minister also accepted that the three governments did not currently have an agreed solution.
The official Downing Street readout said Burnham intended to work with both Mauritius and the United States on the issue. The two prime ministers agreed to remain in close contact.
Foreign ministers expected to meet at UN
Burnham said he hoped Foreign Secretary Ed Miliband and Mauritian Foreign Minister Dhananjay Ramful would be able to meet during the UN General Assembly in New York.
Those discussions are expected to address the future of the agreement and the security arrangements surrounding Diego Garcia.
The inclusion of the United States is essential because the installation is operated jointly by Britain and America and plays a significant role in military operations across the Indian Ocean and surrounding regions.
What did the original Chagos agreement propose?
The treaty signed by the UK and Mauritius would transfer sovereignty over the Chagos Archipelago to Mauritius.
Britain would retain authority over Diego Garcia and continue operating the joint UK-US military facility under an initial 99-year arrangement.
The agreement was presented by the previous Government as a means of providing long-term legal and operational certainty for the base following international challenges to Britain's administration of the islands.
Under the signed terms, British payments to Mauritius were calculated to average approximately £101 million a year. The estimated present-value cost across the 99-year period was placed at around £3.4 billion.
Those figures relate to the existing signed agreement. Burnham has not confirmed whether any revised settlement would retain the same financial terms.
Implementing bill will make no further progress
The Diego Garcia Military Base and British Indian Ocean Territory Bill was introduced to make the domestic legal changes required by the treaty.
However, the 2024–26 parliamentary session ended on 29 April 2026 before the legislation completed all its stages.
Parliament's official bill record states that the legislation will make no further progress. Any Government seeking to implement the agreement would therefore need to introduce fresh legislation or pursue a substantially different course.
The treaty has been signed, but the necessary UK legislation has not been enacted and the sovereignty transfer has not been implemented.
Changed US position complicated the deal
Progress was disrupted after US President Donald Trump publicly criticised the agreement and described it as a mistake.
During parliamentary proceedings in April, ministers said the United States' position appeared to have changed and that it had become impossible at political level to agree an update to the 1966 UK-US arrangements concerning the territory.
That update was considered necessary before the treaty could be ratified and enter into force.
The present discussions are consequently not simply bilateral talks between Britain and Mauritius. A workable settlement must also provide the operational and security assurances required by the United States.
Diego Garcia remains central to allied security
Diego Garcia hosts a major military facility used by British and American forces. Its location provides access to the Indian Ocean, the Middle East and parts of Asia.
The base has supported long-range aircraft, maritime operations, logistics and communications, making its uninterrupted operation a central concern for both London and Washington.
Britain's Strategic Defence Review described Diego Garcia as a bulwark of regional and global security.
Burnham's intervention makes clear that maintaining the base remains the Government's principal objective regardless of how the sovereignty question is ultimately resolved.
No replacement Chagos deal announced
The latest development is a diplomatic commitment rather than a completed agreement.
Burnham has taken political ownership of the unresolved issue and opened direct discussions with Mauritius, but Downing Street has not published revised treaty terms, a legislative timetable or a new financial package.
Any claim that the original deal has been revived unchanged, formally renegotiated or cancelled would go beyond what the Government has confirmed.
The immediate next step is expected to be ministerial engagement during the UN General Assembly, followed by further discussions involving Britain, Mauritius and the United States.
Sources
- Downing Street: Burnham's call with Mauritian Prime Minister Navin Ramgoolam — 21 September 2026
- Reuters: Burnham seeks resolution over Diego Garcia base — 21 September 2026
- UK Parliament: Diego Garcia Military Base and British Indian Ocean Territory Bill
- UK Parliament: Bill status and end of the 2024–26 parliamentary session
- House of Commons Library: Diego Garcia Bill and UK-Mauritius agreement
- Hansard: Diego Garcia Bill debate and changed US position — 14 April 2026