The husband of a British woman being held in an Iranian jail has called for Boris Johnson to provide answers over a blunder that risks lengthening her prison sentence.
Richard Ratcliffe demanded the Foreign Secretary corrects remarks about Nazanin Zaghari-Ratcliffe, while he even suggested Mr Johnson should visit the mother-of-one in Tehran.
Mr Johnson has already been forced to call Iran's foreign minister to ensure his remarks are "not misrepresented", the Foreign Office revealed.
Meanwhile, Labour shadow foreign secretary Emily Thornberry has written to Mr Johnson to insist he must resign should his actions result in Mrs Zaghari-Ratcliffe spending longer in prison.
The 38-year-old has been detained in the Iranian capital since April last year, when she was arrested at Tehran airport as she attempted to return home from a visit to see her family.
Iran's Revolutionary Guard claim she was plotting to overthrow the regime, an allegation Mrs Zaghari-Ratcliffe rejects, and she has been denied access to consular assistance.
The couple's three-year-old daughter Gabriella has also been forced to stay in the country with her maternal grandparents, while Mr Ratcliffe fights for her freedom in London.
Speaking to Sky News, Mr Ratcliffe confirmed his wife is now facing a new charge of spreading propaganda against the regime, which she revealed in a "tearful" phone call to him after a court appearance on Saturday.
The fresh accusation came just days after Mr Johnson told the House of Commons' Foreign Affairs Committee that Mrs Zaghari-Ratcliffe was teaching journalism in Iran.
Both Mr Ratcliffe and his wife's employers, the Thomson Reuters Foundation, deny that was the case, insisting Mrs Zaghari-Ratcliffe was merely on holiday in Iran, a country where the charity do not conduct their work.
He said: "It's been long a demand that we've been making of the Government to be clear that she's innocent, she's was there on holiday and this is outrageous the way a British citizen has been treated."
But Iran's judiciary have seized on Mr Johnson's comments as justification for holding the British-Iranian national.
Mr Ratcliffe revealed his wife could now have her current sentence doubled under Iranian law, as they claim she is now a second-time offender.
He accused the Foreign Secretary of "giving them [Iran] space to be able to smear" his wife.
Although Mr Ratcliffe added he was pleased with Mr Johnson's condemnation of Iran during the committee appearance, in which he also said he would be open to visiting Mrs Zaghari-Ratcliffe.
"We spent a long time asking the Foreign Secretary to engage and he did engage last week," Mr Ratcliffe said.
"I want Nazinin home, I want Gabriella home, so actually – if it was top ask – it would be for him to say something to Parliament and to go over there.
"Aside from whatever's been said, actually the signal politically of going there to visit her is no small thing."
The Thomson Reuters Foundation have also demanded Mr Johnson retract his comments, clarifying Mrs Zaghari-Ratcliffe is a project manager for the charity and has never trained journalists.
Monique Villa, chief executive of the charitable arm of the Thomson Reuters news agency, said: "I see a direct correlation between this statement by Boris Johnson… and the fact that Nazanin was brought once again into court on Saturday 4 November and accused of 'spreading propaganda against the regime'."
She added the latest charge "can only worsen" Mrs Zaghari-Ratcliffe's situation.
Responding to the row, a Foreign Office spokesman said: "Last week's remarks by the Foreign Secretary provide no justifiable basis on which to bring any additional charges against Nazanin Zaghari-Ratcliffe.
"While criticising the Iranian case against Mrs Zaghari-Ratcliffe, the Foreign Secretary sought to explain that even the most extreme set of unproven Iranian allegations against her were insufficient reason for her detention and treatment.
"The UK will continue to do all it can to secure her release on humanitarian grounds and the Foreign Secretary will be calling the Iranian foreign minister to raise again his serious concerns about the case and ensure his remarks are not misrepresented."