Jeremy Corbyn has vowed to return the Chagos Islands to Mauritius after the UK was branded an “illegal colonial occupier” for refusing to hand back the archipelago by the United Nations deadline.

The six-month schedule to return control of the overseas territory came and was set to pass on Friday, with Boris Johnson refusing to recognise a claim of sovereignty over the islands by Mauritius.

The Labour leader vowed to “end colonial rule” and return the islands if he wins the December 12 election, and accused the Conservatives of “shamefully” considering themselves above international law.

Speaking to reporters on a campaign stop in Worksop, the Prime Minister said: “We obviously dispute the claims that are made and we will continue to make those to vindicate our position in international law.”

Mauritius prime minister Pravind Jugnauth said his Government “strongly deplores” the UK’s decision.

“This situation clearly leaves the United Kingdom as an illegal colonial occupier,” he told the National Assembly of Mauritius in anticipation of the deadline passing.

The UN overwhelmingly voted in May to set the six-month deadline for UK withdrawal from the Indian Ocean archipelago, in a major diplomatic blow.

A US Air Force B-52H Stratofortress being towed past another on the flight line at Navy Support Facility Diego Garcia
A US Air Force B-52H Stratofortress being towed past another on the flight line at Navy Support Facility Diego Garcia (Staff Sgt Mary L Smith/PA)

Mr Corbyn, speaking to reporters on the campaign trail in Stoke-on-Trent on Friday, said he would “absolutely” return the islands to Mauritius.

“It’s clear that in refusing to return the Chagos Islands to Mauritius and defying the UN General Assembly and International Court of Justice, this Conservative Government shamefully considers itself to be above international law,” he added in a statement.

“We immediately will enact our manifesto promise to allow the people of the Chagos Islands and their descendants the right to return to the lands from which they should never have been removed.”

The UK evicted Chagossians from the archipelago between 1967 and 1973 so that the US could erect a military base on Diego Garcia, the largest island in the group.

That move, and the islands’ incorporation into the British Indian Ocean Territory, was ruled “unlawful” by judges at the International Court of Justice in The Hague.

While not legally binding, the UN vote heaped diplomatic pressure on Britain to return the territory, with the General Assembly backing the resolution 116 votes to six.

Jeremy Corbyn
Labour Party leader Jeremy Corbyn (Joe Giddens/PA)

Diego Garcia remains a strategically important US military base and has been used for highly controversial rendition flights carrying suspects of terrorism.

The UK purchased the archipelago from Mauritius for £3 million in 1965, when it was still a British colony.

Mauritius, which gained independence from Britain in 1968, maintains the islands are its own.

Asked for a comment, the Foreign Office pointed to a recent ministerial statement saying: “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.”