Guardian defends leaks as MI5 accuses newspaper of damage
9 October 2013 Last updated at 15:42 BST
The Guardian newspaper has defended itself against publication of files leaked by the American intelligence analyst Edward Snowden, after the new head of MI5 said the leaks caused enormous damage.
In his first public speech, Andrew Parker also said security services must be given access to the many means of technology and communication used by terrorists.
Frank Gardner reports.