Material seized from the partner of Guardian journalist Glenn Greenwald "misappropriated" and "classified"
Material seized from the partner of Guardian journalist Glenn Greenwald would harm national security if disclosed, the High Court has heard.
David Miranda, 28, was held at Heathrow under anti-terror laws for nine hours on Sunday August 18 as he changed planes on a journey from Berlin to his home in Brazil.
His partner, Glenn Greenwald, has worked with US whistleblower Edward Snowden on a series of security services exposes, with the seized information deemed "classified" and "misappropriated".
Oliver Robbins, deputy national security adviser for intelligence, security and resilience in the Cabinet Office, outlined why security services and police needed to "make use" of material.
Mr Robbins's written statement indicated no information so far analysed had "identified a journalistic source" or contained "items prepared by a journalist with a view to publication".
"The information that has been accessed consists entirely of misappropriated classified material in the form of approximately 58,000 highly classified UK intelligence documents," Mr Robbins added.
However, following a hearing in London today, Alan Rusbridger, editor-in-chief, Guardian News & Media, said: "Mr Robbins makes a number of unsubstantiated and inaccurate claims in his witness statement.
"The way the Government has behaved over the past three months belies the picture of urgency and crisis they have painted.
"The Government claims that they have at all times acted with the utmost urgency because of what they believed to be a grave threat to national security. However, their behaviour since early June - when the Guardian's first Snowden articles were published - belies these claims."
Mr Rusbridger added: "The Guardian took every decision on what to publish very slowly and very carefully and when we met with Government officials in July they acknowledged that we had displayed a 'responsible' attitude."
David Miranda has launched an application for a judicial review, arguing his detention was a misuse of Schedule 7 of the Terrorism Act 2000 and breached his human rights.
His case is due to be fully aired at a High Court trial in October while a criminal investigation is also under way.