Details from 250,000 leaked documents obtained by the WikiLeaks whistleblowers website were published by a number of newspapers which had been given advance sight of the material, including The Guardian.
The Guardian said it would be publishing details later in the week of cables relating to Britain — including allegations of “inappropriate behaviour” by a member of the Royal Family which was said to have “startled” US diplomats.
The documents were also said to include “serious political criticism” of David Cameron and “devastating criticism” of British military operations in Afghanistan.
Potentially most seriously of all for Britain, The Guardian said that the cables included requests for “specific intelligence” about British MPs.
Both the British and US governments strongly condemned the leaks while insisting that they would not damage relations between the two countries.
US officials have spent recent days frantically contacting friendly governments — including Britain — to brief them about the likely disclosures in the cables in an attempt to limit the diplomatic fallout.
White House press secretary Robert Gibbs said that the disclosure of classified diplomatic communications on the front pages of newspapers around the world would “deeply impact” US foreign interests.
“To be clear — such disclosures put at risk our diplomats, intelligence professionals, and people around the world who come to the United States for assistance in promoting democracy and open government,” he said.
“By releasing stolen and classified documents, WikiLeaks has put at risk not only the cause of human rights but also the lives and work of these individuals, Gibbs said.
The Foreign Office said that such leaks were “not in the national interest” and could damage national security.
A spokesman added: “We have a very strong relationship with the US Government. That will continue.”
The main focus of the material released last night, however, was on US interests elsewhere, according to reports on the websites of The Guardian and the New York Times.
The most striking of the initial disclosures is that Arab leaders have been privately urging the US to take military action to halt Iran’s nuclear programme before it is too late.
The King of Bahrain was quoted as telling US diplomats that Tehran’s nuclear drive “must be stopped”. In another cable, he was said to have warned: “The danger of letting it go on is greater than the danger of stopping it”.
He was said to have been backed by King Abdullah of Saudi Arabia who was said to have repeatedly urged Washington to “cut off the head of the snake” while there was still time.
The cables were said to include a US assessment that Iran has obtained advanced missiles from North Korea that could enable it to strike Western European capitals and Moscow and develop more formidable long-range ballistic missiles.
There were also said to be instructions to US diplomats to spy on the leadership of the United Nations.
They were said to be contained in a series of “human intelligence directives” signed by both the current Secretary of State Hillary Clinton and her predecessor Condoleezza Rice.
One directive requested the specification of telecoms and IT systems used by top UN officials and their staff as well as details of “private VIP networks used for official communication, to include upgrades, security measures, passwords, personal encryption keys”.
Others instruct diplomats to obtain personal details of people they meet including frequent flyer numbers, credit card details, iris scans, fingerprints, and even DNA material.