BORIS JOHNSON burbled yesterday that he “could have been clearer” when he blurted out claims that could keep a British mum locked up in an Iranian jail for an extra five years.

The Foreign Secretary told MPs that Nazanin Zaghari-Ratcliffe, who has been convicted of trying to overthrow the government, was in Iran to teach journalism.

Ms Zaghari-Ratcliffe has denied the charges, insisting she was only in the country so that her daughter could meet her grandparents.

But Mr Johnson denied that his blunder put Ms Zaghari-Ratcliffe in further danger, telling the Commons that he had spoken to his Iranian counterpart Javad Zarif to make it clear that the British government is in “no doubt” that she was not in Iran to overthrow its government.

He accused shadow foreign secretary Emily Thornberry of “deflecting blame” from the Iranian government onto him.

But Labour MP Yvette Cooper told him that it is “not the first time that he has said things that are inaccurate or damaging.”

Calling on him to resign, she said Britain deserves a foreign secretary who is not “too careless or lazy” to fix mistakes rather than “shrugging them off.”

Ms Zaghari-Ratcliffe is serving a five-year sentence for unspecified offences. She was summoned before an Iranian court on Saturday, shortly after Mr Johnson’s comments, to be told she was facing allegations of “spreading propaganda against the state.”

Her employer Thompson Reuters — who said she was not a journalist and worked as a project manager in the company’s media development team — and family have feared that the new allegation could add five more years to her sentence.