LONDON — A pair of High Court judges in Britain granted Julian Assange permission to appeal his extradition to the United States, where he faces charges of espionage for releasing reams of sensitive military and diplomatic files via WikiLeaks in 2010.

It was a legal victory for Assange, as it meant that the 52-year-old WikiLeaks founder would not be whisked away by U.S. marshals. But he is set to remain in the high-security Belmarsh prison, on the outskirts of London, while his legal saga continues in Britain for more months.