The Queen was challenged today for overstepping her powers when she denied the right of thousands of Chagos islanders to return to their homeland in the Indian Ocean.

On the first day of a case that seeks to overturn the current laws that prevent 8,000 Chagosians, who are British citizens, from returning to the Chagos archipelago, the High Court heard that the Queen used the royal prerogative "to remove or exclude British citizens from the territory to which they belong".

Sir Sydney Kentridge, QC, argued that when the Queen approved an "Order in Council" on June 10, 2004, to uphold the 40-year-old eviction of the Chagosians from their homes, she acted outside her authority over the British Indian Ocean Territory to which the Chagos Islands belong.

Sir Sydney said the order was not a "statutory instrument", not subject to any approval by Parliament and was made without any consultation with the Chagosians.

He said the Queen's authority over the Chagos Islands was limited to legislating "for the peace, order and good governance of the territory" and as such, the order was "invalid and of no effect".

Sir Sydney's attack on the Order in Council is at the heart of the case brought by Louis Olivier Bancoult, an electrician, chef and fisherman who was evicted as a boy, along with 3,000 other Chagosians from the territory's main island of Diego Garcia in the middle of the Indian Ocean.

The inhabitants of Diego Garcia were removed from their homes without compensation to make way for the building of an American airbase in 1965. Since its construction, Diego Garcia, which is 1,000 miles off the southern coast of India, has served as the base for air attacks in the Middle East and Afghanistan. It is also one of the facilities under scrutiny in reports on the CIA's "extraordinary rendition" programme for terrorist suspects.

Sir Sydney told the court this morning that the Chagosians, who now mostly live in Mauritius and whose number has grown to 8,000, won the right to return to the outlying Chagos Islands from the High Court in November 2000.

The then Foreign Secretary, Robin Cook, accepted the court’s ruling and said that the Chagosians would be allowed to make their homes on islands other than Diego Garcia.

"They thought they had finally succeeded in establishing their right to return - but that was not to be," Sir Sydney told Lord Justice Hooper and Mr Justice Cresswell.

"On June 10, 2004, the right they thought they had, and believed they had, was removed from them," he said. "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 restored the Government's eviction order that had been quashed by the High Court, Sir Sydney said.

Orders in Council are classified as secondary legislation and are issued by the Privy Council. They often relate to the regulation of professional bodies, or the transfer of responsibilities between government departments. They are not subject to parliamentary scrutiny.

Earlier, on the steps of the High Court, Mr Bancoult, who has travelled from Port Louis, Mauritius, to hear the case was joined by dozens of Chagosian supporters who have settled in Croydon, Surrey.

"The Orders in Council are a secret law shamefully used to by-pass Parliament," said Mr Bancoult. "The Government knew many MPs would be against them. We want to show the British Government has treated us, its own citizens, very shamefully and shown contempt for its own institutions and the judgment of the High Court."

The case, which is expected to last five days with a verdict reserved for a later date, continues.

Explore UK News

• Crime News

• Education News

• Health News

• Scotland News

Times Recommends

• Please help: maimed children of war want their lives back
• Unlocking the cruellest prison
• Prince Charles named in £81m court battle