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WELLINGTON, New Zealand -- Britain needed U.S. intelligence to help thwart a major terror attack. New Zealand relied on it to send troops to Afghanistan. And Australia used it to help convict a would-be bomber.
All feats were the result of a spying alliance known as Five Eyes that groups together five English-speaking democracies, and they point to a vital lesson: American information is so valuable, experts say, that no amount of global outrage over secret U.S. surveillance powers would cause Britain, Canada, Australia and New Zealand to ditch the Five Eyes relationship.
The broader message is that the revelations from NSA leaker Edward Snowden are unlikely to stop or even slow the global growth of secret-hunting, which is increasingly crucial to the security and prosperity of nations.
"Information is like gold," Bruce Ferguson, the former head of New Zealand's foreign spy agency, the Government Communications Security Bureau, told The Associated Press. "If you don't have it, you don't survive."
The Five Eyes arrangement underscores the value of this information -- as well as the limitations of the information sharing.
The collaboration began during World War II when the allies were trying to crack German and Japanese naval codes and has endured. The alliance helps avoid duplication in some instances and allows for greater penetration in others. The five nations have agreed not to spy on each other, and in many outposts around the world, Five Eyes agencies work side by side, allowing for information to be shared quickly.
But Richard Aldrich, who spent a decade researching a book on British surveillance, said some Five Eyes nations have spied on each other, violating their own rules.
The five countries "generally know what's in each other's underwear drawers so you don't need to spy, but occasionally there will be issues when they don't agree" -- and when that happens, they snoop, Aldrich said.
In Five Eyes, the U.S. boasts the most advanced technical abilities and the biggest budget. Britain is a leader in traditional spying, thanks in part to its reach into countries that were once part of the British Empire. Australia has excelled in gathering regional signals and intelligence, providing a window into the growing might of Asia. Canadians, Australians and New Zealanders can sometimes prove useful spies because they don't come under the same scrutiny as their British and American counterparts.
"The United States doesn't share information," said Bob Ayers, a former CIA officer, "without an expectation of getting something in return."
Britain is home to one of the world's largest eavesdropping centers, located about 300 kilometers (186 miles) northwest of London at Menwith Hill. It's run by the NSA but hundreds of British employees are employed there, including analysts from Britain's eavesdropping agency, the Government Communications Headquarters -- or GCHQ. Australia is home to Pine Gap, a sprawling satellite tracking station located in the remote center of the country, where NSA officials work side-by-side with scores of locals. The U.S. also posts three or four analysts at a time in New Zealand, home to the small Waihopai and Tangimoana spy stations.
The intelligence-sharing relationship enabled American and British security and law enforcement officials to thwart a major terror attack in 2006 -- the trans-Atlantic liquid bomb plot to blow up some 10 airliners.
The collaboration, sometimes called ECHELON, takes place within strict parameters. Two U.S. intelligence officials, who spoke on condition of anonymity because they weren't authorized to speak about the program to the news media, said only U.S. intelligence officers can directly access their own vast database.
A Five Eyes ally can ask to cross-check, say, a suspicious phone number it has independently collected to see if there is any link to the U.S., the officials said. But the ally must first show the request is being made in response to a potential threat to Western interests.
Ferguson said that in New Zealand, cooperation with the U.S. improved markedly after the Sept. 11, 2001, terrorist attacks. Still, he said, his agency was kept on a need-to-know basis. He said he never knew what information was being provided to other Five Eyes nations, and none of the countries would have shared all their intelligence anyway.
Ferguson said a small country like New Zealand benefited by a ratio of about five-to-one in the information it received compared to what it provided. He said that as chief of the defense force, a role he held before taking over the spy agency in 2006, he could never have sent troops to Afghanistan without the on-the-ground intelligence provided by the U.S. and other allies. He said New Zealand continues to rely on Five Eyes information for most of its overseas deployments, from peacekeeping to humanitarian efforts. The intelligence is vital, he added, for thwarting potential cyber threats.
In Australia, prosecutors in 2009 used evidence from a U.S. informant who had been at a terrorist training camp in Pakistan to help convict one of nine Muslim extremists found guilty of planning to bomb an unspecified Sydney target. The Australian Security Intelligence Organisation wrote in an email to AP that "intelligence sharing between countries is critical to identifying and preventing terrorism and other transnational security threats."
Canada's Department of National Defence had a similar response, saying it "takes an active role in building relationships with allies. Collaborating with the personnel of the Five Eyes community in support of mutual defense and security issues is part of this relationship building."
Both agencies declined requests to provide more specific information.
In the decades since World War II, the allies have formed various other intelligence allegiances, although few as comprehensive or deep as Five Eyes. While the Snowden revelations will test the relationship, it has survived tests in the past.
New Zealand has long asserted an independent foreign policy by banning nuclear ships, and some are now calling for the country to go further and opt out of Five Eyes. Lawmaker Russel Norman, co-leader of New Zealand's Green Party, is one of many people calling for a public review of the relationship.
"I want to live in a free society, not a total surveillance state," he said. "The old Anglo-American gang of five no longer runs the world."
But John Blaxland, a senior fellow at the Australian National University's Strategic and Defence Studies Centre, said politicians Down Under have often criticized the security relationship until they've gotten into power and been briefed on its benefits.
Then, he said, they tend to go silent.
"The perception is that the advantages are so great, they'd be crazy to give it up," he said.
-- Dodds reported from London. Associated Press writers Lara Jakes and Matt Apuzzo in Washington and Rob Gillies in Toronto contributed to this report.