British Foreign Secretary Boris Johnson prompted an outcry last week with his assertion that a British charity worker serving the past 18 months in prison in Iran was not just visiting the country on holiday as she claimed but in fact training journalists in Tehran.

That is enough to get someone in big trouble in the Islamic republic. The woman's family and employer swore that it was not true.

Johnson was grilled over his remarks in Parliament on Tuesday but refused to apologize. He conceded that he "could have been clearer" when he said last week that Nazanin Zaghari-Ratcliffe was "simply teaching people journalism" in Tehran. The husband of the 37-year-old mother and dual British-Iranian citizen denied that and said Johnson's assertion endangered his wife.

Johnson, a Conservative, came under withering criticism by detractors in the Labour Party who said that the flamboyant secretary had been reckless again and that his remarks last week could lead the Iranians to extend Zaghari-Ratcliffe's sentence, as her husband has charged.

"We can only hope no lasting damage was done as a result of his blunder," said Emily Thornberry, the shadow foreign secretary during the session in Parliament. She charged that Johnson had "imperiled" a British national abroad.

Thornberry went on to call for Johnson's resignation, asking, "How many more times does this need to happen" before Prime Minister Theresa May decides "enough is enough?"

British Iranian Nazanin Zaghari-Ratcliffe in an undated photo. (Handout/Reuters)

Thornberry said that if May lacks the "strength or authority" to fire Johnson, "how about the foreign secretary himself shows a bit of personal responsibility and admits that a job like this, where your words hold gravity and your actions have consequences, it is simply not the job for him?"

Johnson, the mop-haired former London mayor and zealous Brexiteer, has come under criticism before for his shoot-from-the-hip style of speaking, which his supporters find clever and endearing — "Boris being Boris" — and his critics view as tired and buffoonish.

British media report that Johnson is scheduled to fly to Washington this week to meet with senators in Congress and to defend the Iran nuclear deal. President Trump announced recently that he would not certify Iran's compliance with the accord — a position that Britain disagrees with.

An Iranian court in 2016 sentenced Zaghari-Ratcliffe to five years in Iran's notorious Evin prison for attempting a "soft overthrow" of the government — a charge rights groups have slammed as politically motivated. Her young daughter was taken from her and lives now with relatives in Iran.

In October, authorities charged her with new, unspecified crimes that could mean an additional 16 years in prison.
She was summoned to court again Saturday, when the presiding judge accused her of "spreading propaganda against the regime."

A branch of Iran's judiciary on Sunday published an article that said Johnson's statement "shows that Nazanin had visited the country for anything but a holiday." 

Johnson's comments "shed new light" on her case, the article said.

Hadi Ghaemi, executive director of the New York-based Center for Human Rights in Iran, called the courts' treatment of Zaghari-Ratcliffe, who has spent time in solitary confinement, "unjust and inhumane."

Iran has detained and imprisoned a number of dual nationals, including Iranian Americans.

Washington Post correspondent Jason Rezaian spent 543 days in prison in Iran after he was arrested and convicted of espionage. He was released in January 2016 as part of a prisoner swap linked to the start of the nuclear deal Iran signed with world powers.

In Parliament on Tuesday, Johnson pushed back against his critics, saying they were seeking to blame him and the Conservative government for actions taken by the Iranians.

"There's no connection whatsoever between my remarks last week and the legal proceedings in Tehran," he said. 

"Put the responsibility where it truly lies," Johnson said, "with the Tehran regime."

The Foreign Office said that Johnson telephoned Iranian Foreign Minister Mohammad Javad Zarif on Tuesday to discuss the case of Zaghari-Ratcliffe, who was arrested while visiting the country with her daughter last year.

Zaghari-Ratcliffe's family and her employer say that she was on vacation in Iran when she was detained.

In his remarks Tuesday, Johnson said Zarif informed him that developments in the Zaghari-Ratcliffe case had nothing to do with his remarks.

Johnson said he would visit Iran in the coming weeks and planned to highlight the case with the Tehran government. He called negotiations for the rapid release of Zaghari-Ratcliffe sensitive and ongoing.

Monique Villa, chief executive of Zaghari-Ratcliffe's employer, the Thomson Reuters Foundation, issued a statement calling for Johnson to correct his "serious mistake" about her training journalists in Iran.

"Like Richard Ratcliffe, her husband," Villa said, "I see a direct correlation between this statement by Boris Johnson, who rightly condemned the treatment that Nazanin has received in Iran, and the fact that Nazanin was brought once again into court on Saturday 4 November, and accused of 'spreading propaganda against the regime.' "

Cunningham reported from Istanbul.