UK Foreign Secretary Boris Johnson is in Iran’s capital Tehran on Saturday, raising hopes that Anglo-Iranian political prisoner Nazanin Zaghari-Ratcliffe could be freed after 22 months.

Johnson is scheduled to see Iranian counterpart Mohammad Javad Zarif today.

The Foreign Secretary said on Friday that the discussion will be about issues such as the conflict in Yemen. Iranian Foreign Ministry spokesman Bahram Qassemi described talks on “latest developments pertaining to Tehran-London relations, particularly in trade and economic sectors, as well as leading regional and international issues”.

However, the context for Johnson’s trip is his unwitting elevation of Zaghari-Ratcliffe’s detention last month, when he wrongly said that she was training journalists inside Iran when she was detained in April 2016. In fact, she and her 2-year-old daughter were visiting Zaghari-Ratcliffe’s mother

The error gave the Iranian judiciary the pretext to apply further pressure on Zaghari-Ratcliffe, an employee of the Thomson Reuters Foundation, by threatening to increase her five-year sentence. She was immediately summoned to a court, with talk that her prison term could be raised to 21 years. Iranian State media aired broadcasts accusing her, on specious “evidence”, of being a spy seeking regime change.

After several days, Johnson finally admitted his mistake. Amid pressure to resign, he said he would go to Tehran to pursue the case.

Zaghari-Ratcliffe’s husband Richard said on Friday that he is “waiting on tenterhooks and biting his nails”. The couple’s daughter Gabriella, whose passport was confiscated by authorities, is still in Tehran with her grandmother.

Maintaining the pressure even as Johnson arrive, the Iranian judiciary has scheduled another hearing on Sunday for Zaghari-Ratcliffe.

Richard Ratcliffe said Johnson will try to visit Nazanin in jail and meet the head of the Iranian judiciary, Sadegh Amoli Larijani.

Iranian State outlet Press TV, reporting on Johnson’s imminent arrival, did not mention the Zaghari-Ratcliffe case.