Prime Minister David Cameron has strongly rebuffed Argentina's president over her call for the UK to return the Falkland Islands.

The Argentinian president, Cristina Fernandez de Kirchner, had earlier reignited the row over the future of the Islands by publishing an open letter to the PM accusing Britain of colonialism and demanding the Falklands be returned to Argentina.

This afternoon a spokesman for Mr Cameron said Falkland Islanders had shown "a clear desire to remain British" and that their interests would be protected.

The Foreign Office (FCO) also commented today using the micro-blogging site Twitter.

The FCO account said: "The people of the Falklands are British and have chosen to be so. They remain free to choose their own futures and have a right to self-determination as enshrined in the UN charter. There are three parties to this debate, not just two as Argentina likes to pretend. There can be no negotiations on the sovereignty of the Falkland Islands unless and until such time as the islanders so wish."

President Fernandez earlier launched a fierce attack on British "colonialism" and demanded the return of "Las Malvinas", in a letter published as an advert in a number of British newspapers.