The High Court in London has dealt a setback to thousands of islanders battling for compensation from the British Government.
What started the dispute?
The forced removal by the British Government of around 2,000 islanders from the Chagos group of islands, in the Indian Ocean, between 1967 and 1973.
They were moved so the United States could build a military airbase on the island of Diego Garcia, the biggest of the archipelago.
The islanders, who with descendants now number up to 5,000, live in Mauritius but are desperate to return to their homeland.
The community lives in slum conditions, suffers high unemployment and complains of racist treatment by the indigenous population.
What is the aim of the court case?
The action on behalf of surviving Chagossians or their dependants is against the British Government.
It aims to recover a so far undetermined amount of compensation, to achieve restitution of property and declarations relating to the entitlement to return to the islands, and measures making such a move possible.
What is the background to the court case?
In a November 2000 court ruling, two judges said there was "no source of lawful authority" to justify the way the islanders had been moved.
They quashed the 1971 Immigration Ordinance, which was enacted at the time of the removals to give them legal authority and cleared the way for construction of the US military base on
The ruling also granted the islanders British citizenship and as a result about 100 came to settle in the UK, around Crawley, near Gatwick airport.
They have since been at the centre of a wrangle between local and central government about who should support them.
What is the British Government's position?
The government's case rests on arguing the Chagossians only ever had contractual rights to the islands, which could be terminated at short notice.
At the time of the removals, the UK said the islanders - descendants of African slaves and Indian plantation workers - were not native but simply temporary labourers.
The Foreign Office says feasibility studies need to be undertaken before any of them can return home, while the US military is opposed to the whole idea.
What has the US done with the territory?
A massive construction effort was launched on Diego Garcia in 1976, and ten years and £300m later it was fully operational as a US airbase.
It was used during the 1990 Gulf War and again for missions supporting action in Afghanistan in 2001 and the invasion of Iraq in early 2003.
The island, and the rest of the Chagos archipelago, remains under British Indian Ocean Territory control, and is subject to UK law. A small detachment of Royal Marines provide local security and enforce immigration and customs rules.