Documents said to have been leaked by whistleblower Edward Snowden apparently show that a number of telecoms companies allowed GCHQ access to undersea cables which carry their phone and internet traffic, allowing them to see details of customers' phone calls and email conversations.
Vodafone and BT, and US-based Verizon, were revealed by Germany's Suddeutsche newspaper which claimed to have details of a spy programme, codenamed Tempora, which allows GCHQ to tap into fibreoptic cables and store data.
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