Guardian Editor-in-Chief Alan Rusbridger dismissed the statement as containing "unsubstantiated and inaccurate claims," and questioned the danger, arguing that the government had done little to address the issue before Miranda's detention.
"The way the government has behaved over the past three months belies the picture of urgency and crisis they have painted," Rusbridger said. "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 behavior since early June when the Guardian's first Snowden articles were published belies these 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. But Friday's decision expanded that remit, allowing the material to also be examined for "specified criminal grounds." The government revealed the criminal investigation into Snowden's leak of classified material to the Guardian during a court hearing last week.
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."
Robbins' statement cited a New York Times article suggesting that Snowden downloaded his material en masse a process called "scraping." The British government believes that Snowden "indiscriminately appropriated material in bulk and that this information, or at least some of it, is the same material that the claimant was couriering for Mr. Greenwald."
However, Robbins said the government was still seeking to decrypt some of the material seized. They were able to look at some of it because Miranda was carrying "on his person" a handwritten piece of paper containing the password for one of the encrypted files.