UK activist Muhammad Abdur Rabbani has been charged with obstruction of justice after refusing to provide encryption passwords to police at an airport stop in London. He is due to appear in court in Westminster, England on June 20th.

Rabbani is being charged under the UK’s controversial Terrorism Act, which allows police to compel British subjects to turn over passwords to encrypted devices. Rabbani was initially stopped in November, and arrested when he refused to provide passwords to local police.

Rabbani, who works for the international human rights group Cage, claims the devices contained privileged information relating to a US client. “I really do think that any professional faced with the same dilemma would do all that they could to protect their clients' private and personal information," he said in a statement to ZDNet.

While the US constitution provides more legal protections, similar stops have become increasingly common at US airports, particularly as Customs officials have stepped up scrutiny of travelers’ social media accounts. In January, NASA scientist Sidd Bikkannavar was forced to unlock his phone as part of a Customs search, despite his claims that the phone contained sensitive material.