British High Court judges on Wednesday dismissed a claim by David Miranda, the partner of ex-Guardian journalist Glenn Greenwald, that his detention at London's Heathrow airport under anti-terror laws last year was unlawful. Greenwald was working at the time with the Guardian newspaper and other publications on articles about US and British spying, based on highly-classified data leaked by former US National Security Agency contractor Edward Snowden. Miranda, a Brazilian citizen, was transporting some of the encrypted data -- including 58,000 British intelligence documents -- from Berlin to Rio de Janeiro when he was stopped while in transit at Heathrow on August 18, 2013. Backed by a coalition of freedom of speech organisations, Miranda challenged his detention in the High Court, claiming it was unlawful and breached his human rights.