The article below was originally published by The Guardian

Britain’s “outright defiance” of a UN deadline to hand the Chagos Islands to Mauritius by Friday, in a final act of African “decolonisation”, has been condemned by Mauritius and the globally-scattered communities of exiled islanders.

The UK’s refusal to end its occupation of the Indian Ocean archipelago is expected to be marked by protests outside the UK high commission in the Mauritian capital, Port Louis, organised by those who were forcibly deported more than 40 years ago and their descendants.

The Labour party’s election manifesto, published on Thursday, pledges to allow Chagossians to resettle in their homeland.

Earlier this year, the UN general assembly voted by an overwhelming majority of 116 to six countries in favour of a motion condemning Britain’s occupation of the remote islands and demanding what the Foreign Office terms British Indian Ocean Territory (BIOT) be reunified with Mauritius.

An advisory opinion by the International Court of Justice (ICJ), in The Hague, found the islands had been illegally severed from Mauritius in the 1960s. The president of the ICJ, Abdulqawi Ahmed Yusuf, urged the UK and other member states to “complete the decolonisation of Mauritius”.

The UK regards neither the ICJ judgment nor the UN motion as binding.

The UN vote in May, which underlined Britain’s diplomatic isolation in the aftermath of the Brexit referendum, set a six-month deadline for UK withdrawal, which expires on Friday. The Chagos archipelago is the last African territory to be held by the UK

Diego Garcia, the largest island in the archipelago, is now a strategically-important US military base used by American bombers on long-range missions and, in the past, for rendition flights carrying terrorism suspects.

Speaking at the UN last month, Jagdish Dharamchand Koonjul, the permanent representative of Mauritius, said: “The response of the United Kingdom to [the UN deadline of 22 November] has been one of outright defiance.”

Koonjul described the UK’s position as disrespectful of the ICJ and the UN. “The time has come for the United Kingdom to comply with the international rule of law which it has so long championed,” he said.

The UK’s representative, Dame Karen Pierce, said Britain remained clear that it held sovereignty over BIOT and was providing a £40m support package to improve the livelihoods of Chagossians.

About 1,500 islanders were forcibly deported from 1968 to 1973 so Diego Garcia could be leased to the US for an airbase. They have never been allowed to return apart from a few short “heritage” visits.

Prof Philippe Sands QC, who represented Mauritius at The Hague, said: “The failure to give effect to the [ICJ] ruling and general assembly decision is lawless and deeply regrettable, a reflection of a continuing colonial mindset. It undermines the UK’s supposed commitment to the rule of law.

“It will serve merely to enhance that sense of international isolation, no different from South Africa in relation to Namibia in the 1970s.

“In the eyes of many, the forcible removal of the Chagossians, and the continuing refusal to allow them to return, after the ICJ and general assembly have spoken so clearly, is akin to a crime against humanity – all the more so after 22 November. The court has made crystal clear that Chagos is and has always been a part of Mauritius.”

Most of the islanders and their descendants live in Mauritius, the Seychelles or the UK, where there have been attempts to deport third-generation Chagossians on the grounds that even if their grandparents would have been entitled to UK residency they are not.

Olivier Bancoult, the leader of the Chagos Refugees Group UK, said protests were planned outside the British high commission in Port Louis on Friday.

He said: “[We] call on all world leaders – and particularly the UK government – to take this opportunity to engage directly with the Chagossian community … and to recognise Chagossians’ right to determine their own future, and the future of their islands.

“It’s time the government engaged directly with the Chagossian community across the world, deliver support for Chagossian return and offer proper support for those still living in exile.”

Among those who have called on the UK to respect the ICJ ruling is the Labour leader, Jeremy Corbyn, who sent a letter to Theresa May in the summer expressing concern that “the government appears ready to disregard international law and ignore a ruling of the international court and the right of the Chagossians to return to their homes”.

Third-generation Chagossians who come to the UK via the Seychelles or Mauritius can face deportation. The Home Office initially told Jeanette Valentin, who lives in Milton Keynes, that both of her daughters, Taniella and Nesta, would be removed when they reached the age of 20.

Lawyers intervened and successfully obtained citizenship rights for both teenagers. “They can now go to university in Britain,” a relieved Valentin said at the time.

Alexander Finch, a solicitor at the law firm Fragomen, who took up her case, added: “Had Jeanette been able to pass on British citizenship to her children this application, and its costs, would never have been necessary.

“We hope the Home Office will review its policy towards third-generation Chagossians recognising their unique historical connection to Britain.”

A Foreign Office spokesperson said: “The UK has no doubt as to our sovereignty over the British Indian Ocean Territory (BIOT), which has been under continuous British sovereignty since 1814. Mauritius has never held sovereignty over the BIOT and the UK does not recognise its claim.”

Photo courtesy: Fiona Hanson/PA