What has Boris Johnson done, and why is it so bad even for him?

Boris Johnson has apologised 12 days after his “mistake” in comments that risked lengthening the prison sentence of a British woman, Nazanin Zaghari-Ratcliffe, who is currently incarcerated in Iran.

The Foreign Secretary returned from Brussels to answer an urgent question on the detention of Ms Zaghari-Ratcliffe, a mother-of-one, who was arrested in Tehran 19 months ago.

The situation has escalated in recent weeks following Mr Johnson’s comments and has led to calls from politicians and members of the public that he should step down.

Here is everything you need to know:

Mr Johnson told a parliamentary committee that a 38-year-old British Iranian woman who was arrested at Tehran and jailed for five years was “simply teaching people journalism”. This was a contradiction to her claims that she was on holiday visiting her family.

Mr Johnson went on to apologise for the “distress and suffering” caused by his remarks, adding: “I do apologise, I do apologise and of course I retract any suggestion that she was there in a professional capacity.”

Mr Johnson has a history of making gaffes, but risking lengthening a British citizen’s jail sentence in a foreign country has generated an even greater intensity of criticism than most of his previous misdemeanours.

A couple of months ago Mr Johnson made what was described as a “stunning” blunder during a visit to Burma’s most sacred temple. The Foreign Secretary recited lines from Rudyard Kipling poem Mandalay, which is written through the eyes of a retired British serviceman in Burma and also references kissing a local girl.

Last month Mr Johnson sparked outrage after he said the Libyan city Sirte could be the new Dubai and that "all they have to do is clear the dead bodies away".

After Mr Johnson’s comments, Ms Zaghari-Ratcliffe was summoned back to court and received further charges. She currently faces allegations of spying and attempting to topple the Iranian government and could have her sentence increased due to Mr Johnson’s comments.

Ms Zaghari-Ratcliffe’s employer, the Thomson Reuters Foundation, a charity organisation, are adamant that Mr Johnson’s comments were not correct.

Ms Zaghari-Ratcliffe is a dual-citizen of both Iran and Britain but this is something that Iran does not recognise. This has meant that she has been given consular assistance in her case.

Now, given the latest comments from Mr Johnson, Iranian state TV has claimed they were an “unintended confession” and she been called for a further trial.

They are insistent that Ms Zaghari-Ratcliffe was attempting to overthrow the government and spying.

The British Government’s line is that Ms Zaghari-Ratcliffe and have been adamant they are looking into what can be done to be of assistance.

Government ministers, including Environment Minister Michael Gove have defended Mr Johnson for his comments. When asked why she was in Iran when she was arrested Mr Gove broke from the official Government line that she was there on holiday to instead say he did not know.

She is currently serving a five-year sentence and after a second trial there are fears her sentence could be more than doubled.

There have been allegations that Ms Zaghari-Ratcliffe has been subjected to torture and her husband, Richard Ratcliffe, said that she was on the verge of a “nervous breakdown” and also said that lumps had been found in her breasts.

He also said that could not believe that Mr Johnson had made comments that could have potentially worsened her situation.

Mr Johnson and Mr Ratcliffe are set to meet for face-to-face discussions. He has urged the Foreign Secretary to escort him to Iran to visit his wife and child.

It has been reported that the Government was considering offering Ms Zaghari-Ratcliffe “diplomatic protection” to try and speed up her release.

Mr Johnson has also said he will make a visit to Iran by the end of this year.