Edward Snowden leaks: UK 'let NSA store email addresses'
The UK allowed the US National Security Agency to keep the mobile phone numbers and email addresses of ordinary Britons from 2007, according to media reports.
Channel 4 News, external and the Guardian, external said existing rules were modified in 2007 to allow the US to keep information swept up incidentally about Britons not suspected of criminal activity
The reports are based on documents leaked by whistleblower Edward Snowden.
The Foreign Office said it did not comment on such "speculation".
BBC Security Correspondent Gordon Corera reports.