The international director of Cage, Muhammad Rabbani, has been charged under the Terrorism Act after refusing to hand over passwords to his laptop at Heathrow airport.
Rabbani, who regards it as a privacy v surveillance test case, said he intended to fight the charge. "I am innocent of these charges that have serious implications for journalists, lawyers and human rights," he said.
He is due to appear at Westminster magistrates court on 20 June.
Rabbani, 35, from London, is involved through Cage in investigating torture cases. He said he was stopped at Heathrow in November returning from one of the Gulf states where he had been investigating a torture case allegedly involving the US.