Decolonisation or Strategic Retreat?
The UK’s decision to hand sovereignty of the Chagos Islands to Mauritius marks an important moment in British foreign policy. Framed by Prime Minister Keir Starmer’s government as a long-overdue act of decolonisation, the deal has sparked security concerns in Washington and accusations of strategic weakness from Conservative MPs and foreign policy hawks.
While the agreement allows the US-UK military base on Diego Garcia to remain operational for 99 years, critics including Donald Trump’s Secretary of State, Marco Rubio have warned that the move could expose the base to Chinese espionage and weaken Britain’s influence in the Indo-Pacific.
This deal is about more than just sovereignty, it is a test of Britain’s post-Brexit role on the world stage. Is this a diplomatic victory that strengthens the UK’s legitimacy in international law? Or is it a self-inflicted retreat, undermining British leverage at a time of rising geopolitical tensions?
A Legacy of Displacement and Dispute
For decades, the Chagos Islands have been a source of legal and diplomatic controversy. When Mauritius gained independence from Britain in 1968, the UK retained control of the Chagos Archipelago, later leasing Diego Garcia to the United States for military use. This agreement led to the forced removal of over 1,000 Chagossians, many of whom have been fighting for their right to return ever since.
The UK has faced increasing international isolation over its continued control of the islands. In 2019, the International Court of Justice (ICJ) ruled that the UK’s claim to Chagos was illegal, and the UN General Assembly overwhelmingly voted for Britain to return the territory to Mauritius.
Facing pressure from allies and international bodies, the Starmer government negotiated a deal with Mauritius in October 2024, agreeing to hand over sovereignty while ensuring that Diego Garcia remains under UK-US control.
But what seemed like a diplomatic win has now become a political flashpoint – both domestically and in Washington.
Washington’s Security Fears: “An Opportunity for Communist China”
The US-UK base on Diego Garcia is a strategic linchpin for American military operations in the Indian Ocean. The island has been used to launch airstrikes in Iraq and Afghanistan, monitor maritime activity, and support Western security interests in the Indo-Pacific.
However, US Republicans – led by Marco Rubio – are deeply sceptical of the deal. In a private call with UK Foreign Secretary David Lammy, Rubio challenged the UK government over whether the agreement could allow China to expand its influence near Diego Garcia.
Rubio publicly warned:
“The Chagos deal is concerning as it would provide an opportunity for communist China to gain valuable intelligence on our naval support facility in Mauritius. This poses a serious threat to our national security interests in the Indian Ocean and threatens critical US military posture in the region.” – Marco Rubio
Some analysts argue that Mauritius, under economic pressure from Beijing, could allow Chinese naval or intelligence vessels to operate in the region. If the waters around Diego Garcia fall under Mauritian control, the fear is that Chinese ships could loiter in the area, conducting surveillance on US naval activity.
The UK government has firmly denied these concerns. When asked whether the deal increased Chinese influence, the Prime Minister’s spokesman responded:
“We’ve always been clear that isn’t the case. This deal secures the long-term base that is so crucial to regional security. It protects UK and US national security interests but also protects regional security.”
Despite these reassurances, the White House under Donald Trump could still re-evaluate the deal – with Britain likely needing to negotiate further assurances with Washington.
UK Political Fallout: A Self-Inflicted Weakness?
While Labour presents the Chagos deal as a diplomatic victory, the agreement has triggered backlash in Westminster, particularly from Conservative and Reform UK figures who view the decision as a strategic blunder.
Critics argue that this move:
- Weakens the UK’s Indo-Pacific presence, reducing its influence in a critical military region.
- Creates uncertainty for UK-US relations, especially under a Republican administration sceptical of the deal.
- Sets a precedent for other British overseas territories, such as the Falklands or Gibraltar, potentially emboldening Argentina or Spain to push for sovereignty changes.
For those who backed post-Brexit “Global Britain” ambitions, the UK’s voluntary ceding of power over Chagos signals a contradiction in foreign policy. While the UK insists that the deal strengthens security ties, critics fear it diminishes Britain’s standing in global military strategy.
Final Thought
The Chagos Islands deal represents a defining moment for Britain’s place in the world. The UK government insists that this agreement is about righting historical wrongs and securing long-term stability for Diego Garcia. However, the backlash from US Republicans and security hawks suggests that Britain’s credibility as a strategic power is now being questioned.
The real test will be how Washington reacts. If Donald Trump’s administration demands new security guarantees, London could find itself renegotiating a deal it has already signed.
Britain must prove that it remains a serious geopolitical player and strengthen its alliances and defending its interests in the Indo-Pacific.
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