BORIS Johnson has been criticised after offering a grudging half-apology for a mistake which could keep a British citizen in an Iranian jail an extra five years.

Adding to doubts about his suitability for high office, the Foreign Secretary refused to say sorry for a false claim he made last week about Nazanin Zaghari-Ratcliffe, but said it may have been "taken out of context" and caused "anxiety".

Mr Johnson had told a Commons committee that Ms Zahari-Ratcliffe, who was detained as a spy and coup-plotter 18 months ago, had been training journalists in Iran.

This contradicted her family’s assertion that she had been on a holiday with her infant daughter.

The Iranian judiciary's High Council for Human Rights seized on the comments, and told Ms Zahari-Ratcliffe, an employee of the Thomson Reuters Foundation, that as a result she faced new allegations of “propaganda against the state”.

Her family fear it could double her five-year sentence.

Her husband, Richard Ratcliffe, has now requested a meeting with the Foreign Secretary.

Mr Johnson spoke on Tuesday to his his Iranian counterpart, Javad Zarif, about the case.

Later he endured a bruising session in the Commons, where he insisted his remarks had been misunderstood and accused his opponents of political point-scoring.

He said: “My point was that I disagreed with the Iranian view that training journalists was a crime, not that I wanted to lend any credence to Iranian allegations that Mrs Zaghari-Ratcliffe had been engaged in such activity. I accept that my remarks could have been clearer in that respect and I’m glad to provide that clarification.”

His Labour shadow Emily Thornberry called on him to offer an unreserved apology and asked how many times Mr Johnson had to mess up before Theresa May sacked him.

She said: “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?”

After several other MPs demanded an apology, Mr Johnson said he was sorry “if any words of mine have been so taken out of context, so misconstrued, as to cause any kind of anxiety for the family of Nazanin Zaghari-Ratcliffe”.

The performance added to concerns on his own benches that he lacked the gravitas and discipline for one of the most sensitive roles in government.

Tory MP Anna Soubry tweeted: “The lack of contrition is as shameful as the original error. Boris Johnson doesn't understand magnitude of the job & responsibility he holds."

One Tory MP also told The Spectator that Mr Johnson had “no dignity and integrity”.

Labour former minister Chris Bryant: "There's not a single eight-year-old that wouldn't be able to tell the Foreign Secretary how to do his job better.

"The honest truth is if you can't show some contrition today then the honest truth is he shouldn't be in his job as our people aren't safe."

In the Lords, former LibDem leader Menzies Campbell said: “The truth is the Foreign Secretary has annoyed our allies and embarrassed our friends. He was never fit for purpose and should never have been appointed to his present role and he should go now.”

Downing Street said Mrs May backed Mr Johnson and he did not need to apologise.

A spokesperson said: “What was important, and which has been welcomed, was for the Foreign Secretary to be absolutely clear that M Zaghari-Ratcliffe was on holiday in Iran when she was arrested and that that was the sole purpose of her visit."