Great British PAC seeks legal advice after judges incorrectly state that controversial Diego Garcia Bill completed its parliamentary passage.
QUESTIONS have been raised over a factual error in a major Court of Appeal judgment concerning the Chagos Islands, after five judges incorrectly stated that legislation implementing Britain’s controversial agreement with Mauritius had completed its passage through Parliament.
The discrepancy appears in the opening paragraph of a judgment handed down by the British Indian Ocean Territory (BIOT) Court of Appeal on Thursday, 12 November 2026.
The judgment, delivered by Mr Justice Lane with the agreement of four other appeal judges, concerns a legal battle involving Chagossian islanders who returned to their ancestral homeland earlier this year.
However, paragraph one contains a statement about the parliamentary progress of the Diego Garcia Military Base and British Indian Ocean Territory Bill which is contradicted by Parliament’s own official records.
The judges wrote:
“The bill by which this Treaty will be incorporated into United Kingdom law (The Diego Garcia Military Base and British Indian Ocean Territory Bill) completed its legislative stages in both Houses of Parliament in January 2026. The bill awaits final enactment and royal assent.”
But the legislation had not completed its parliamentary passage.
Although the Bill received its third reading in the House of Lords on 12 January 2026, disagreements over amendments remained unresolved.
The legislation returned to the House of Commons on 20 January, before further consideration was required in the Lords.
It subsequently fell when Parliament was prorogued on 29 April 2026, more than six months before the Court of Appeal delivered its judgment.
The official parliamentary website confirms that the Bill would make no further progress following the end of the 2024–2026 parliamentary session.
The discrepancy raises questions about how the incorrect parliamentary information came to be included in a judgment agreed by five senior judges.
The court also referred back to the Bill’s supposed legislative status in paragraph 68, when considering the legal effect of the agreement between Britain and Mauritius.
The judgment correctly acknowledged that the treaty had not been incorporated into domestic law. However, the judges’ description of the Bill as awaiting enactment and Royal Assent did not reflect its actual parliamentary position.
The discrepancy was brought to the attention of Great British PAC by a senior member of the House of Lords, prompting the organisation, which has been supporting legal challenges concerning the Chagos Islands, to examine its potential implications.
Claire Bullivant, CEO of Great British PAC, said:
“This is an extraordinary discrepancy in a judgment concerning such a serious and consequential matter.
“Five appeal judges have agreed a judgment which states that the Diego Garcia Bill completed its parliamentary stages in January and was awaiting Royal Assent. Yet Parliament’s own official records show that this simply isn’t true.
“The Bill had not completed its passage and fell when Parliament was prorogued in April, more than six months before this judgment was handed down.
“How did such a fundamental factual error make it into the final judgment, and why was it not picked up?
“We are checking the matter with the legal teams to establish whether this is simply an error in the court’s description of events or whether it has any bearing on the legal reasoning and conclusions.
“We are not suggesting that this automatically invalidates the judgment, but when matters of sovereignty, national security and the rights of the Chagossian people are at stake, accuracy is absolutely essential.
“The public is entitled to expect the highest standards of accuracy from our courts, particularly in a case of this importance.”
The ruling arose from proceedings involving four British Chagossians who arrived on Île du Coin in February 2026 without permission from the BIOT authorities.
In March, the BIOT Supreme Court ruled in their favour, quashing a provision of the territory’s 2004 Constitution Order which prevented individuals from claiming a right of abode, as well as notices ordering their removal.
The BIOT Commissioner appealed, and on 12 November the Court of Appeal overturned the earlier ruling, finding that the Supreme Court had exceeded its jurisdiction in examining the lawfulness of the constitutional provision.
The appeal judges also identified procedural errors and deficiencies in the earlier court’s reasoning.
The Court of Appeal’s conclusions rested on several legal grounds, and it has not been established that the incorrect description of the Bill’s parliamentary progress affected the outcome.
The discovery nevertheless adds a new issue for examination as the legal battle over the islands continues.
Great British PAC has been supporting Chagossian legal proceedings challenging decisions affecting their ancestral homeland, including efforts to protect the rights of islanders who have returned.
The wider dispute centres on the controversial agreement signed by former Prime Minister Keir Starmer’s Government and Mauritius in May 2025, under which Britain would surrender sovereignty over the Chagos Archipelago, including Diego Garcia, to Mauritius, only to pay billions of pounds for the right to continue operating the strategically vital joint UK-US military base.
The extraordinary arrangement would see Britain relinquish sovereignty over territory it already controls, before paying Mauritius under a 99-year lease agreement to retain the use of a military facility that is considered critical to British and American national security.
The original implementing legislation has fallen, and the future of the agreement remains unresolved.
Whether the factual error in the Court of Appeal judgment has any legal significance is now a matter for examination by the lawyers involved in the case. We will keep you updated.
Read the judgment in full here:
