Edward Snowden leaks: UK 'let NSA store email addresses'
Date published: 25th November 2013
The Foreign Office said it did not comment on such "speculation".
Under the seven-decade-old UK-US agreement on intelligence sharing, Britain and America's intelligence agencies are not supposed to collect information on each other without permission.
Before 2007, if the US - on one of its other operations - had come across a British mobile phone number or email address, it would not have been able to keep it.
But, according to the documents, after the rules changed, the US was allowed to keep those records to analyse them for the specific purpose of "contact chaining".
That means looking at the connections between different phone numbers or email addresses.To continue reading click here