Partner of former Guardian journalist Glenn Greenwald had his rights violated by detention, lawyers say at high court

This article is more than 6 years old

This article is more than 6 years old

Lawyers for David Miranda, partner of the former Guardian journalist Glenn Greenwald, are at the high court to argue that his nine-hour detention by police at Heathrow airport in the summer was unlawful.

The claim, challenging controversial powers used under schedule 7 to the Terrorism Act 2000, maintains that Miranda was not involved in terrorism and says his right to freedom of expression was curtailed.

The Brazilian national was stopped as he passed through Heathrow airport on 18 August. He was in transit between Berlin and Rio de Janeiro after meeting the film-maker, Laura Poitras, who has been involved in breaking revelations based on documents leaked by NSA whistleblower Edward Snowden.

Miranda's lawyers say the Metropolitan police misused schedule 7 and that his detention was a violation of his human rights. They have sought information about why Miranda was stopped and why his laptop, phone and electronic equipment were seized.

The legal action is against the home secretary and the commissioner of the Metropolitan police. Lawyers for both the police and Home Office argue the Brazilian was stopped because of concerns about national security and terrorism.

A final draft of the police's internal port circulation sheet (PCS), which formally set out the reasons for Miranda's detention, said that "intelligence indicates that Miranda is likely to be involved" in espionage activity that had the potential to "act against the interests of UK national security". Disclosure of the material he was carrying, it said, fell within the definition of terrorism.

The PCS document, drawn up in consultation with the intelligence services, also said: "We assess that Miranda is knowingly carrying material, the release of which would endanger people's lives.

"Additionally the disclosure, or threat of disclosure, is designed to influence a government, and is made for the purpose of promoting a political or ideological cause. This therefore falls within the definition of terrorism and as such we request that the subject is examined under schedule 7."

At the start of the hearing lawyers for the Home Office said they accepted that among items examined by police there was journalistic material.

Stephen Kovats QC, for the Home Office, told the court: "We now do not deny that amongst material that Mr Miranda was carrying is journalistic material … material that has been worked upon by a journalist with a view to publication."

He added: "We do not understand that raw Snowden data is journalistic material."

The hearing is expected to last two days.