Boris Johnson’s remarks on the imprisonment of British-Iranian mother Nazanin Zaghari-Ratcliffe had “traumatic effects” and enabled a propaganda campaign to be waged against her, according to her husband.

Grilled about his handling of the case last night, the frontrunner to be the next Conservative leader claimed his erroneous comments while foreign secretary didn’t “make any difference”.

He had suggested during a committee in 2017 that Ms Zaghari-Ratcliffe had been involved in training journalists – a statement he was forced to apologise for and which was used by Iranian authorities to justify her detention.

“If you point the finger at the UK, all you are doing is exculpating those who are truly responsible, which is the Iranian Revolutionary Guard,” Mr Johnson said during Tuesday’s Conservative leadership debate on BBC1.

But Ms Zaghari-Ratcliffe’s husband, Richard, vehemently dismissed Mr Johnson’s claim, and said of course his remarks had “consequences”.

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He said the main difference made by the then-foreign secretary’s comments was to enable a “propaganda campaign” to be run against Ms Ratcliffe in Iran, and on the state-run broadcaster, Press TV.

“We saw a couple of weeks... afterwards, [Iran] accusing her of being a spy and [saying] the foreign secretary approved it, which obviously had very traumatic effects for her,” he told BBC Radio 4’s Today programme.

Mr Ratcliffe added that Mr Johnson’s comments were used to justify a second court case against his wife in Tehran, and said they “probably even caused it” and had been used “to discredit her ever since”.

He continued: “Even a couple of weeks ago there was stuff on Press TV, again recycling his words and saying listen, the foreign secretary confirmed that she was there working.”

Pressed on wether blame should be directed towards the Iranian regime and the issue of decades worth of debt over a historic arms deal, Mr Ratcliffe replied: “Obviously it’s the Iranian authorities that have imprisoned Nazanin and the Iranian authorities that have a practice of harsh diplomacy but at the same time the foreign secretary’s words then were important and promises have consequences.

“Perhaps the bigger problem he did was when essentially the press was briefed that money was going to be paid and expectations were raised and he said ‘no stone will be unturned’. And then that didn’t happen. We’ve gone from ‘no stone unturned’ to ‘not my fault’.”

The remarks from Mr Ratcliffe come as he stages a hunger strike outside the Iranian embassy in London, in solidarity with his wife who began the third day of her own protest on Saturday.

Richard Ratcliffe campaigning for his wife's release on Mother's Day (PA)

Ms Zaghari-Ratcliffe was arrested on 3 April 2016 at Imam Khomeini Airport in Tehran as she prepared to board a plane back to the UK after visiting relatives and is serving a five-year sentence in the notorious Evin Prison.