Islanders who now want to return home have launched a historic legal challenge to their removal in the High Court in London.
Hundreds of islanders, known as Ilois, were forced to move away from the Chagos islands during the late 1960s to allow the US to build a strategically located base on the main island of Diego Garcia, halfway between Africa and south-east Asia.
Islanders who now want to return home have launched a historic legal challenge to their removal in the High Court in London.
Sir Sydney Kentridge QC, appearing for the islanders told the court: "This application for judicial review arises from a very sad and by no means creditable episode in British colonial history."
He told Lord Justice Laws, sitting in London with Mr Justice Gibbs that, between 1967-73, the UK took steps to remove the whole existing population from the 65-island Chagos Archipelago.
This involved some 2,000 people according to the islanders, but half that number according to the British Government.
'Dumped on the dockside'
The QC said: "It is not in dispute that this was done without the consent of the Ilois, without consultation with the Ilois and without any arrangements for their re-settlement. They were taken largely to Mauritius, and a few to the Seychelles.
"When the ships carrying them arrived at Mauritius they were simply dumped on the dockside with no provision made at all for their housing or subsistence.
"It was only some time much later that some financial and other assistance was given by the UK government, and also by the Mauritius government."
At the time, Mauritius had mass unemployment and the Ilois brought there found themselves "on the fringes of society".
With several of the applicants in court listening, Sir Sydney added: "Many of them still live in poverty, or near poverty."
It is estimated that approximately 500 of the evicted islanders are still alive.
Monday's legal action was brought in the name of a representative islander, Louis Bancoult, chairman of the Chagos Refugee Group in Mauritius.
Sir Sydney described how Mr Bancoult was born in 1964 on Peros Banhas, when the Chagos islands were part of the colony of Mauritius, which the British had taken from the French during the Napoleonic wars.
In November 1965, the Chagos islands were separated from Mauritius by Order in Council to form part of a new colony named the British Indian Ocean Territory (BIOT).
Weapons discount
This was because of an agreement between the UK and the US that the islands, of which Diego Garcia was the principal atoll, should be available to the US government for defence and communication purposes.
As part of the deal, the UK Government reportedly received an £11m discount off its US-made Polaris nuclear weapons system.
It also reportedly paid Mauritius £3m to take the islanders off its hands.
In 1967, Mr Bancoult and his family went to Mauritius - some 1200 miles away - for medical treatment, and were prevented from returning to the islands and had reluctantly remained in Mauritius ever since.
In a statement issued on Monday, the Foreign Office said Britain had already arranged for Ilois community members to visit the island and assess the current condition.
"We are taking the advice of consultants to assess whether people could return to the outer islands and what the environmental impact would be.
"Their work is not complete and we are asking them to continue it," the statement said.
Foreign Secretary Robin Cook, whose department will be defending the action in the High Court, was one of the young MPs who expressed his outrage at the eviction when the story came to light in 1975.
The court case has been seen as an embarrassment to Mr Cook, who promised an "ethical foreign policy" when he took over in May 1997.
The hearing is expected to last for five days.