Boris Johnson’s “mistaken” comments about a British mother jailed in Iran on spying charges she strongly denies are still being used by the Islamic republic to discredit the prisoner, her husband has said.

Richard Ratcliffe was also scathing about the government’s attempts to defend the ex-foreign secretary’s comments about his wife, Nazanin Zaghari-Ratcliffe, in broadcast interviews which left the family feeling like ministers were “briefing against us”.

They also felt “orphaned” when Johnson resigned over Brexit, having taken up the case personally but failed to secure Nazanin’s release.

Johnson in November 2017 wrongly stated the charity worker had been in Iran to teach journalism, when in fact she had been on holiday, and his remarks were cited as evidence against her in court four days later. She has been in jail for more than three years.

Ratcliffe spoke to HuffPost UK with Johnson way out in front in the Tory leadership race and facing questions over his record in office as he looks increasingly like a prime minister-in-waiting.

Ratcliffe told HuffPost UK: “Clearly he made a mistake, which became amplified by the way the Iranian authorities responded to it, and used it to justify a second court case against Nazanin, and played them endlessly on Iranian TV.

“And those comments are still brought out by the Iranian authorities when it suits them to discredit Nazanin, as recently as a couple of weeks ago.”

Johnson’s comments were however not the “key issue”, Ratcliffe said.

“At the time, I resented more the way various ministers were sent out onto the airwaves, like Michael Gove on Andrew Marr to pretend it hadn’t been a mistake and further muddy Nazanin’s innocence.

“It felt like briefing against us.

“That was when I had to ask the Foreign Office to remind the cabinet that the government knew that Nazanin was on holiday and was not doing anything they were accusing her of.

“It felt Nazanin’s case was being treated like a political football – and it had somehow become about Boris, and Brexit, and not about Nazanin.

“As a campaigner you always want the government to be under some pressure – but focused on our survival, not theirs.”

Johnson eventually met Ratcliffe and travelled to Tehran for talks with president Hassan Rouhani in December 2017, but failed to secure Nazanin’s release.

The foreign secretary then quit the government in July of the following year, following David Davis out of the cabinet in protest at Theresa May’s Brexit plan.

Ratcliffe said: “When I finally met Boris Johnson, he was sincere and engaged, and did not BS me behind closed doors.

“He promised to leave no stone unturned, and travelled to Tehran – which calmed things down in Iran.

“Obviously the frustration came after, when he wasn’t able to deliver on that promise, which had consequences for Nazanin and others. We felt a bit orphaned when he left office.”

Ratcliffe said Johnson’s successor, Jeremy Hunt, who is also battling for the Tory leadership had been “pretty straight”, “made clear he personally cares” and granted Nazanin diplomatic protection.

“He was the first person in the government to recognise Nazanin’s innocence unambiguously in public,” he said.

“Whatever happens I will be grateful for that.”

But he said both foreign secretaries could have done more, Ratcliffe said.

This week, he launched a campaign in conjunction with other families with relatives detained abroad to secure from the new prime minister stronger protections for Britons held overseas.

“Has either done enough? By definition, no – since Nazanin and the others remain in prison,” Ratcliffe said.

“While I recognise the challenge, I don’t think that the government – as a government – has challenged sufficiently Iran’s hostage diplomacy. I don’t think it has adequately engaged with the underlying issues, but kept them a bit hidden away.

“Government’s first duty is to protect its citizens, from torture and unfair imprisonment.

“That is what we wrote as families to all the PM candidates: the important thing about the new British passport is actually not whether it is blue or red, but how they make real the protections on the inside page.”

On April 3 2016, Nazanin was arrested with their infant daughter Gabriella at Tehran’s Imam Khomeini Airport as she prepared to board a plane back to the UK after visiting relatives.

The British-Iranian is serving a five-year sentence in Tehran’s notorious Evin Prison after she was convicted of membership of an illegal group.

The trial by a revolutionary court in Tehran was widely condemned as unfair and she denies the charges against her.