UK security adviser outlines government fears for intelligence agents on seized documents

It was the first time the government has offered specific reasoning behind why security services and police are so concerned about material seized from David Miranda – the partner of Guardian journalist Glenn Greenwald. Miranda was detained at Heathrow Airport and questioned for nearly nine hours under terrorism legislation earlier this month, but the government had earlier said only that it required access to the files on national security grounds.

Greenwald has written stories based on material leaked by former U.S. National Security Agency contractor Edward Snowden. Miranda, a 28-year-old university student, was travelling home to Brazil after visiting Germany, where he met with Laura Poitras, a U.S. filmmaker who has worked with Greenwald on the NSA stories.

Oliver Robbins offered a sweeping view of the government concerns before Britain’s High Court, saying the 58,000 classified U.K. documents are “highly likely” to describe techniques used in counter-terror operations and could reveal the identities of U.K. intelligence officers abroad.

“It would cause real harm to the work of the U.K.’s national security and intelligence agencies if an intelligence officer were to have his or her identity disclosed on anything other than an authorized and limited basis,” Robbins said in the statement dated earlier this week ahead of a Friday hearing.

Guardian Editor-in-Chief Alan Rusbridger dismissed the statement as containing “unsubstantiated and inaccurate claims.”

The statement came as the Guardian and the government agreed to allow the authorities to keep sifting through documents – as long as it was on national security grounds. The agreement came after the Guardian unsuccessfully sued last week to stop police from combing through digital material seized from Miranda.

Miranda’s attorneys described the decision as a pragmatic one – since the government was looking through the documents already – and said that Miranda had decided he would make his full argument in October.

“Given the vague doomsday prophecies which the police and Home Office have put before the court, our client decided that the full hearing in October was the better forum in which to argue these fundamental issues of press freedom,” Miranda’s lawyer Gwendolen Morgan said in a statement. “He hopes that – in open court – the defendants’ assertions will be fully tested.”