The Prime Minister has said the future of the Falkland Islands is up to the people who live there - not Argentina.
David Cameron rebuffed claims by Argentine president Cristina Fernandez de Kirchner that Britain is a colonial power and that the Islands should be handed over.
Mr Cameron told her she should "listen" to the result of a referendum to be held on the Island, and if the people chose to remain British they would have his "100%" backing.
He said: "The future of the Falkland Islands should be determined by the Falkland Islanders themselves, the people who live there. Whenever they have been asked their opinion, they say they want to maintain their current status with the United Kingdom.
"They're holding a referendum this year and I hope the president of Argentina will listen to that referendum and recognise it is for the Falkland Islanders to choose their future, and as long as they choose to stay with the United Kingdom they have my 100% backing."
Mr Cameron, on a visit to Preston, responded to questions on the Islands after the row over their future was reignited by an open letter written by the president of Argentina, calling on him to relinquish British control.
The letter, published as an advert in the Guardian, claimed that Argentina was "forcibly stripped of the Malvinas" - the Argentinian name for the islands - in "a blatant exercise of 19th century colonialism".
The 59-year-old president, who made several calls for the return of the islands during last year's 30th anniversary of the two countries going to war, urged the Prime Minister to abide by United Nations resolutions she says back the Argentinian cause.
Mr Cameron and Ms de Kirchner clashed over the Falklands when the pair came face to face at the G20 summit in Mexico last June.
He rejected her demand for negotiations over the sovereignty of the islands and told her to respect the result of a referendum, when the Falklanders will vote on whether they wish to retain their ties with Britain.