Desmond Tutu was among five Nobel Prize laureates putting pressure on Britain to negotiate with Argentina over sovereignty of the Falklands Islands last night.
The anti-apartheid campaigner signed a letter organised by Argentine artist Adolfo Pérez Esquivel, who campaigned against the military dictatorship in his country.
"Since 1982, the UN general assembly has continuously renewed the call through the adoption of resolutions requesting that the two countries sit down and talk," the statement said.
"We therefore request that you review the British government's position of refusing to dialogue on this matter, and that your government comply with United Nations resolutions calling for the initiation of talks with the Republic of Argentina."
The letter comes amid attempts to isolate Britain on the international stage at a nuclear summit in Seoul, South Korea.
Yesterday Argentine foreign minister Hector Timerman accused Britain of flouting a treaty prohibiting nuclear materials from South America.
"Argentina demands that extra-regional power that has recently sent a submarine capable of carrying nuclear arsenal to patrol the South Atlantic waters confirm the absence of nuclear weapons in the region," he said.
Nick Clegg, who was attending the summit, replied: "I'm afraid I'm duty-bound to respond to the insinuations made by the Argentinean delegation of militarisation of the South Atlantic by the British government. These are unfounded, baseless insinuations."
The other signatories to the letter were Rigoberta Menchu, a Mayan activist leader in Guatemala, Mairead Maguire of Ireland, US national Jody Williams and Iran's Shirin Ebadi.
The British government, following the principle of self-determination, refuses to negotiate over the sovereignty of the Falklands unless its islanders give their consent.