The phone, internet and email records of UK citizens not suspected of any wrongdoing have been analysed and stored by America's National Security Agency under a secret deal that was approved by British intelligence officials, according to documents from the whistleblower Edward Snowden.
In the first explicit confirmation that UK citizens have been caught up in US mass surveillance programs, an NSA memo describes how in 2007 an agreement was reached that allowed the agency to "unmask" and hold on to personal data about Britons that had previously been off limits.
The memo, published in a joint investigation by the Guardian and Britain's Channel 4 News, says the material is being put in databases where it can be made available to other members of the US intelligence and military community.
Britain and the US are the main two partners in the 'Five-Eyes' intelligence-sharing alliance, which also includes Australia, New Zealand and Canada. Until now, it had been generally understood that the citizens of each country were protected from surveillance by any of the others.