Diego Garcia Military Base and British Indian Ocean Territory Bill

Lord Biggar Excerpts

2nd reading
Tuesday 4th November 2025 Lords Chamber

[Lord Biggar (Con)]

My Lords, the treaty that the Bill before us would ratify vaunts its righting of the historic wrong done to the Chagossians, while doing little for them. It signals its virtue, without much exercising it. That has been made plain several times over the past few hours, so I will not labour it.

As my noble friend Lord Hannan of Kingsclere has rightly urged, the treaty’s real concern is not the Chagossians but completing the decolonisation of Mauritius. The Government accept the ICJ’s 2019 advisory opinion that, in effect, the detachment of the Chagos Islands from Mauritius in 1965 was unlawful because it defied UN General Assembly resolutions in 1960 and 1966. These declared that:

“Any attempt aimed at … disruption of the national unity and the territorial integrity of a country is incompatible with … the Charter of the United Nations”.


The 1966 one urged that the UK take no action that would dismember the territory of Mauritius and violate its territorial integrity.

However, this principle of non-partition is nonsense. Supporting the 1960 resolution, the president of the General Assembly, Irish diplomat Frederick Boland, invoked Ireland’s loss of its historic integrity to illustrate the injustice of partition. He thereby expressed the Irish nationalist’s typical historical blindness. The island of Ireland had never been a political unit, apart from its union with Great Britain; and, as the noble Baroness, Lady Foster of Aghadrumsee, has already well said, there is no natural law prescribing that a geographical integrity has to be a political one. On the contrary, there can be good reasons for dividing it. Ireland was divided in 1922 because Irish republicans wanted home rule so much that they were prepared to use violence to attain it, while Irish unionists disliked it so much that they were prepared to take up arms to oppose it. Ireland was petitioned to prevent civil war—a justified act of political prudence. What is more, if the principle of non-partition were applied impartially, applicants to the ICJ would be clamouring for the restoration of the territorial integrity of British India and the return of the Gulf states and Burma to rule by Delhi. Oddly, we hear no such clamour.

The 1966 resolution is no less absurd than the 1960 one. It appeals to the national unity of Mauritius—as if the Chagos Islands were not separated by more than 1,000 miles of Indian Ocean, and as if the islanders were an integral part of the Mauritian people; but many Chagossians feel as Mauritian as Irish republicans feel British. The only connection between Mauritius and the Chagos Islands is an accident of colonial administrative convenience. Talk of some national unity that was ruptured in 1965 is an opportunistic fiction.

Notwithstanding its opportunistic absurdity, the principle of non-partition was invoked and confirmed by the ICJ in its advisory opinion. What is more, the court used that principle to adjudicate a crucial point of contention between Mauritius and the UK, notwithstanding the fact that, when originally submitting itself to the court, the UK explicitly excluded its jurisdiction over such a dispute.

Among the Government’s several, shifting justifications for signing the treaty is said to be the fear that a subsequent international tribunal—such as the International Tribunal for the Law of the Sea—would use the ICJ’s opinion to make a binding judgment against the UK. Therefore, to avoid that embarrassment, the Government prefer to give up the fight now, conceding sovereignty and negotiating an expensive lease.

I agree with the noble Lord, Lord Jay of Ewelme, that international law deserves respect. However, I also agree with the noble Lord, Lord Weir of Ballyholme, that respect requires much more than blind, slavish compliance. When international law embodies an absurd principle that is opportunistically and partially applied outside of its agreed jurisdiction, it brings the international order into disrepute and corrodes the law’s authority.

For the sake of upholding confidence in international law, the UK should stand its ground, argue the strong, rational case for its sovereignty over the Chagos Islands, expose the imprudence and partiality of the General Assembly’s resolutions, and remind the international community that the ICJ has no jurisdiction. If some international tribunal were irresponsible enough to issue a binding judgment against the UK on the basis of the ICJ’s opinion, the UK should, with respect, not comply with it.

I have no doubt that that would cost us diplomatic good will in progressive circles that are entranced by an idealised view of international law, but we have no good will to lose with ideologically hostile states such as China, Russia and Iran. The rest of the so-called global South is not a politically uniform bloc; it embraces nations ranging from India to Nigeria and Peru, which have divergent—sometimes opposing—interests and views. They would not all react with equal disapproval to our principled non-compliance. Some might even be impressed by a self-confident Britain’s refusal to yield to opportunistic lawfare, in bold defence of the law’s integrity.

This treaty is disingenuous in championing the Chagossians and slavish in its blind compliance with absurd and partial law. For those reasons, we should not ratify it.