A review of the use of anti-terror powers to detain David Miranda at Heathrow has been launched, hours after judges were told police had started a criminal investigation based on the data seized.
David Anderson, the independent reviewer of terrorism legislation, has written to Home Secretary Theresa May to outline his reasons for looking at Mr Miranda’s detention at Heathrow on Sunday.
He said he wanted to establish if the power contained in Section 7 of the Terrorism Act 2000 was “lawfully, appropriately and humanely used”.
The Home Office said it was “right” for Mr Anderson to undertake such a review to ensure the law had been applied properly.
In separate developments, judges at the High Court were told a criminal investigation was now under way after police seized “tens of thousands of pages of material” from Mr Miranda’s electronic equipment during his nine-hour detention.
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.
Jonathan Laidlaw QC, appearing for the Met Police, said a mass of material had been discovered by officers, who are still examining the seizures.
Mr Laidlaw said: “That which has been inspected contains, in the view of the police, highly sensitive material, disclosure of which would be gravely injurious to public safety.
“Thus, the police have now initiated a criminal investigation.”
Mr Laidlaw was fighting an application by Mr Miranda for an interim injunction to prevent the Government, its agencies and the police from further “inspecting, copying or sharing” the material until London’s High Court can hear his challenge to the legality of the seizures in the near future.
His lawyers are seeking judicial review, arguing his detention was a misuse of Schedule 7 of the Terrorism Act 2000 and breached his human rights.
Lord Justice Beatson and Mr Justice Kenneth Parker adjourned Mr Miranda’s injunction application until next Friday.
In the meantime, they made orders that the seized data could continue to be examined but only for national security purposes and the protection of the public.
The judges said this included whether Mr Miranda himself was involved in the commission, preparation or instigation of acts of terrorism.
Matthew Ryder QC, for Mr Miranda, told the judges his client was questioned and property in his possession was seized “under threat of criminal prosecution in a coercive use of Schedule 7, which was unlawful”.
In his letter to Mrs May, Mr Anderson explained he wanted to provide “independent scrutiny” of the use of the powers.
He said: “My intention is to concentrate on the use made by police of the Schedule 7 powers in this case. This will inevitably involve consideration of whether the powers were lawfully, appropriately and humanely used.”