LONDON — British spies are running an online eavesdropping operation so vast that internal documents say it even outstrips the United States' international Internet surveillance effort, the Guardian newspaper reported Friday.
The paper cited British intelligence memos leaked by former National Security Agency contractor Edward Snowden to claim that U.K. spies were tapping into the world's network of fiber optic cables to deliver the "biggest internet access" of any member of the Five Eyes — the name given to the espionage alliance composed of the United States, Britain, Canada, Australia, and New Zealand.
That access could in theory expose a huge chunk of the world's everyday communications — including the content of people's emails, calls, and more — to scrutiny from British spies and their American allies. How much data the Brits are copying off the fiber optic network isn't clear, but it's likely to be enormous. The Guardian said the information flowing across more than 200 cables was being monitored by more than 500 analysts from the NSA and its U.K. counterpart, GCHQ.
"This is a massive amount of data!" the Guardian quoted a leaked slide as boasting. The paper said other leaked slides, including one labeled "Collect-it-all," gave hints as to the program's ambition.
"Why can't we collect all the signals all the time?" NSA chief Lt. Gen. Keith Alexander was quoted as saying in another slide. "Sounds like a good summer project for Menwith" — a reference to GCHQ's Menwith Hill eavesdropping site in northern England.
The NSA declined to comment on Friday's report. GCHQ also declined to comment on the report, although in an emailed statement it repeated past assurances about the legality of its actions.
"Our work is carried out in accordance with a strict legal and policy framework which ensures that our activities are authorized, necessary, and proportionate," the statement said.
The Guardian, whose revelations about America and Britain's globe-spanning surveillance programs have reignited an international debate over the ethics of espionage, said GCHQ was using probes to capture and copy data as it crisscrossed the Atlantic between Western Europe and North America.
It said that, by last year, GCHQ was in some way handling 600 million telecommunications every day — although it did not go into any further detail and it was not clear whether that meant that GCHQ could systematically record or even track all the electronic movement at once.
Fiber optic cables — thin strands of glass bundled together and strung out underground or across the oceans — play a critical role in keeping the world connected. A 2010 estimate suggested that such cables are responsible for 95 percent of the world's international voice and data traffic, and the Guardian said Britain's geographic position on Europe's western fringe gave it natural access to many of the trans-Atlantic cables as they emerged from the sea.
The Guardian said GCHQ's probes did more than just monitor the data live; British eavesdroppers can store content for three days and metadata — information about who was talking to whom, for how long, from where, and through what medium — for 30 days.
The paper quoted Snowden, the leaker, as saying that the surveillance was "not just a US problem. The U.K. has a huge dog in this fight ... They (GCHQ) are worse than the U.S."
Snowden, whose whereabouts are unknown, faces the prospect of prosecution in the United States over his disclosures, and some there have called on him to be tried for treason. Snowden has expressed interest in seeking asylum in Iceland, where a local businessman said he was prepared to fly the leaker should he request it.
Attempts by The Associated Press to reach Snowden have so far been unsuccessful.