Anglo-Iranian charity worker Nazanin Zaghari-Ratcliffe is marking her second anniversary in a prison in Iran’s capital Tehran.

Zaghari-Ratcliffe, an employee of the Thomson Reuters Foundation, was seized at the airport on April 3, 2016. Her daughter Gabriella, 3, whose passport was also taken, is still with her grandmother in Tehran.

Despite no evidence being presented publicly against her, Zaghari-Ratcliffe was sentenced to five years in prison for espionage. Iranian authorities have threatened to up add to 16 years to the punishment.

Last autumn, as pressure grew for the charity worker’s release, Iranian State TV presented a few e-mails, taken out of context, to claim that Zaghari-Ratcliffe — then serving as an administrator for BBC Media Action — had tried to encourage journalists in the overthrow of the regime after the disputed 2009 Presidential election.

Hopes briefly rose in December as British Foreign Secretary Boris Johnson remained Tehran, but he returned with no commitment from Iranian officials to end Zaghari-Ratcliffe’s imprisonment.

Richard Ratcliffe said that he is trying to use the anniversary to maintain the campaign for the release of his wife:

There is a need to recharge spirits – particularly after the disappointment of the Foreign Secretary’s mission failing to deliver and Nazanin becoming caught up in this government standoff [between Iran and the UK] – so we wanted the anniversary to be an occasion where we drew positive energy.

Speaking at an event in north London, Ratcliffe called for the intervention of Prime Minister Theresa May:

Nazanin is still in prison, so in simple terms, the Foreign Secretary has not done enough.

The Prime Minister is more important, and just as we were pushing to meet the Foreign Secretary, at some point, if that is not enough, we have to push up another level and that’s the Prime Minister.

The UK Foreign Office said,”We will not be providing a running commentary on every twist and turn.”