David Cameron last night saluted the bravery of the Armed Forces in a speech to mark 30th anniversary of the liberation of the Falkland Islands – and warned Argentina that Britain is "ready and willing" to stand up for them again.

Speaking at the annual Falkland Islands Government reception in London, the Prime Minister said he was "proud" of those who had served in the 1982 conflict, adding that the country "will always be in your debt".

Mr Cameron added that the Falklands was enjoying economic growth and industries such as tourism and fishing were "thriving". He also delivered a strong warning to Argentine President Cristina Fernandez de Kirchner, pictured, who was in New York addressing the UN at the same time, that there would be "no negotiation" over sovereignty of the islands.

"There is only one shadow on the horizon. And that is the aggression from over the water," Mr Cameron said. "We've seen the president trying to restrict the movement of Falklands vessels, banning charter flights to and from Argentina and today, escalating the debate at the UN."

He continued: "My message to the government of Argentina is this: the UK has no aggressive intentions towards you. Accusations of militarisation and nuclear threats are hyperbole and propaganda.

"But do not under-estimate our resolve. Threats will not work, attempts to intimidate the islanders will not succeed, because Britain stands ready and willing to stand up for the Falkland Islanders at any time."

Earlier in the day, around 400 islanders braved freezing conditions to gather next to Liberation Memorial in the capital of Stanley to thank those who ended the 74-day occupation of the remote British Overseas Territory.