(Reuters) - British authorities claimed the domestic partner of reporter Glenn Greenwald was involved in "terrorism" when he tried to carry documents from former U.S. intelligence contractor Edward Snowden through a London airport in August, according to police and intelligence documents.

Greenwald's partner, David Miranda, was detained and questioned for nine hours by British authorities at Heathrow on Aug. 18, when he landed there from Berlin to change planes for a flight to Rio De Janeiro, Brazil.

After his release and return to Rio, Miranda filed a legal action against the British government, seeking the return of materials seized from him by British authorities and a judicial review of the legality of his detention.

At a London court hearing this week for Miranda's lawsuit, a document called a "Ports Circulation Sheet" was read into the record. It was prepared by Scotland Yard - in consultation with the MI5 counterintelligence agency - and circulated to British border posts before Miranda's arrival. The precise date of the document is unclear.

"Intelligence indicates that Miranda is likely to be involved in espionage activity which has the potential to act against the interests of UK national security," according to the document.

"We assess that Miranda is knowingly carrying material the release of which would endanger people's lives," the document continued. "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..." http://www.huffingtonpost.com/2013/11/02/david-miranda-terrorism-glenn-greenwald-british_n_4199838.html