Lawyers acting for the journalist's partner held for nine hours under anti-terror laws have won an order to stop the Government and police "inspecting, copying or sharing" data seized from him - except "for the purpose of protecting national security".
David Miranda's legal team were granted the order, which will run until Friday 30 August.
The High Court will then consider further Mr Miranda's application for an interim injunction to stop examination "until the legality of that seizure has been determined by this court".
Matthew Ryder QC, appearing for Mr Miranda, told the court the legal challenge had been brought "to protect the confidentiality of sensitive journalistic material".
Mr Miranda has launched an application for judicial review, arguing that his detention was a misuse of Schedule 7 of the Terrorism Act 2000 and breached his human rights.
The Brazilian is the partner of Guardian journalist Glenn Greenwald who has worked with US whistleblower Edward Snowden on a series of security services exposes.
Mr Miranda was held without charge at Heathrow Airport for the maximum time permitted under the anti-terror legislation as he changed planes on a journey from Berlin to his home in Brazil on Sunday.
Today's order was granted by Lord Justice Beatson and Mr Justice Kenneth Parker after hearing the Home Secretary considered it was in the interests of national security to examine the data "without delay".
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