The detention of journalist Glenn Greenwald's partner during a London layover was justified by national security, a British court ruled Wednesday. The High Court said counter-terrorism agents engaged in an "indirect interference with press freedom" when they held David Miranda at Heathrow International Airport for 9 hours, the Guardian reported. But the judges said the detention and seizure of Miranda's computer files was legal. Greenwald, a former New York lawyer who worked for the Guardian from August 2012 to October 2013, was one of the top journalists working with former U.S. National Security Agency contractor Edward Snowden. He lives in Rio de Janeiro with Miranda. Miranda was stopped at Heathrow on his way back to Brazil from Germany, where he had been meeting with Laura Poitras, a filmmaker who had also been working with Snowden. The Guardian had paid for Miranda's ticket and he was carrying an external hard drive that contained classified British documents. Greenwald argued that the government could not justify Miranda's detention on national security grounds since he had taken care to make sure nothing published would put U.S. or British security at risk. "We're disappointed by today's judgment, which means that an act designed to defeat terrorism can now be used to catch those who are working on fundamentally important issues," Guardian News & Media said in a statement. "The judgment takes a narrow view of what 'journalism' is in the 21st century and a very wide view of the definition of 'terrorism'. We find that disturbing." Miranda pledged to appeal Wednesday's decision.