Liam Fox has insisted Boris Johnson did not make a "serious gaffe" over the case of a British woman being held in Iran – despite fears the Foreign Secretary's comments could lengthen her sentence.
Nazanin Zaghari-Ratcliffe has been jailed in Iran since April last year, and her husband has called on Mr Johnson to correct his remarks after Iran's regime used his words as justification for continuing to detain his wife.
The Foreign Secretary told the House of Commons' Foreign Affairs Committee: "When I look at what Nazanin Zaghari-Ratcliffe was doing, she was simply teaching people journalism, as I understand it."
Both her husband, Richard Ratcliffe, and her employers, the Thomson Reuters Foundation, strongly dispute this, saying the British-Iranian national was in the country on holiday with her young daughter.
The row has led to calls for Mr Johnson to consider his position should Mrs Zaghari-Ratcliffe, a charity worker, have her sentenced increased.
Former Conservative minister Anna Soubry branded the Foreign Secretary's actions "appalling", adding: "In 'normal' times Boris Johnson would have been sacked long ago."
But Mr Fox, the International Trade Secretary, dismissed the criticism as a plot to discredit his Cabinet colleague.
Asked whether Mr Johnson should be sacked over the controversy, Mr Fox told Sky News: "I don't believe it is a serious gaffe.
"I think people in the Iranian regime, which is a very brutal regime, are using this as an excuse to hold a UK citizen in the most tenuous, if not illegal, circumstances."
Three days after Mr Johnson's comments, the 38-year-old was hit with fresh charges of spreading propaganda against the country's regime, which could double her sentence.
She was initially arrested as she attempted to return to London in 2016 on accusations of plotting to overthrow the Iranian regime.
Mr Johnson is expected to call Iran's foreign minister to ensure his remarks are not "misrepresented".
In his defence of the Foreign Secretary, Mr Fox urged caution amid the backlash at Mr Johnson's actions.
He added: "The Foreign Secretary was making very clear at that select committee that what was happening at the present time is totally unacceptable, that the behaviour of the regime is internationally unacceptable.
"We should be giving support to him in that because that is the best was to put pressure on the regime.
"I think what we're seeing here is an attempt to discredit the Foreign Secretary without thinking, first of all, what the impact may be and what excuses it may give to the Iranian regime to act improperly.
"We always have to be very circumspect about what we say in a free society about the implications it may have elsewhere."
Mr Ratcliffe, whose daughter has not been allowed to return to the UK while her mother is in jail, has also suggested the Foreign Secretary should visit his wife in Tehran.