The director of campaign group Cage has been charged under the Terrorism Act.
Muhammad Rabbani faces a charge of failing to disclose his password after being detained at Heathrow Airport under counter-terrorism stop-and-search powers, the organisation has said.
Mr Rabbani was stopped at Heathrow in November, but refused to give officers access to his phone and laptop.
Cage describes itself as an independent advocacy group “working for those impacted by the War on Terror”.
The Metropolitan Police confirmed that Mr Rabbani, 36, attended an east London police station on Wednesday.
A spokesman for Cage said Mr Rabbani was charged with wilfully obstructing or seeking to frustrate a search examination under Schedule 7 of the Terrorism Act 2000 over the incident at the airport in November.
That law gives officers special powers to question and detain for up to six hours any individual passing through a UK port, airport, international rail terminal or border area.
Cage, whose main role is to support those who have been affected by UK counter-terrorism legislation, said Mr Rabbani had been released on bail and would be challenging the charge.