Islanders who were evacuated from a British territory in the Indian Ocean in the 1970s have begun a High Court bid to win the right to return home.
Diego Garcia became a military base in the 1970s
Residents of Diego Garcia in the Chagos archipelago were moved to Mauritius in 1971, when Britain leased the island to the US to use as a military base.
A court in 2000 ruled the expulsions were illegal, but last year their return was stopped by government order.
Lawyers for the islanders say their human rights were violated.
The lawyers have asked the High Court to declare the government order "invalid and of no effect".
The legal action has been brought by Louis Bancoult, who was evacuated from the islands as a boy.
Most of the islanders went to Mauritius, but over the years families found it hard to settle and became impoverished - so much so that a number of individuals have committed suicide. The refugees have been campaigning to return ever since their expulsion.
The Chagosians are UK passport holders who are entitled to reside in Britain and, over the years, about 800 of them have taken up that option in search of a better life.
However, many islanders want the government to fulfil a promise they say was made by Robin Cook, while foreign secretary, that they would be allowed to return to outlying islands in the Chagos group.
They claim the promise was made after the treatment they received was condemned in a High Court judgement five years ago.
On Tuesday, Sir Sydney Kentridge QC told the High Court how in November 2000 the Chagosians were jubilant when Mr Bancoult won a High Court victory quashing earlier government orders excluding them from the islands.
Sir Sydney, acting for Mr Bancoult, said: "They thought they had finally succeeded in establishing their right to return - but that was not to be."
He told the court that on 10 June 2004, "the right they thought they had, and believed they had, was removed from them".
He said it was removed: "not by Parliament, but by Her Majesty the Queen acting through Orders in Council on advice from the Secretary of State for the Foreign and Commonwealth Office."
The Orders, which were issued through the Privy Council, restored the government ban quashed by the High Court.
The islanders have accepted that they cannot live on Diego Garcia because of its use as a military base.
Its facilities were used in the bombing of Iraq and Afghanistan.
And the base was recently at the centre of allegations that it is one of the locations being used to house secret detainees in the US' so-called war on terror.
'Concepts of morality'
Richard Gifford, one of the lawyers who is representing the islanders, has said the government has a moral duty to return them to their homeland.
He said: "I've no doubt it is quite inconvenient to provide for the return of a population to their homeland, but that really doesn't square with concepts of morality, justice or anything else in this day and age.
"It's the sort of thing they might have done in the 17th or 18th Century."
Of the 2,000 people moved off the hundreds of tiny coral atolls, 1,500 were taken to Mauritius and the remainder to the Seychelles.