The husband of Nazanin Zaghari-Ratcliffe says he has held "positive and constructive" talks with Boris Johnson over her detention in Iran.
Richard Ratcliffe met for an hour with the Foreign Secretary where they discussed the possibility of the pair travelling to Iran.
Though no date for Mr Johnson's trip has been fixed, he was described as "keen" for Mr Ratcliffe to accompany him.
Speaking after Wednesday's meeting, Mr Ratcliffe said he had pressed for diplomatic immunity for his wife.
Such a move has not been ruled out, according to Labour MP Tulip Siddiq.
The meeting was the first time Mr Johnson and Mr Ratcliffe have come face to face and follows criticism of the Foreign Secretary over comments he made suggesting Ms Zaghari-Ratcliffe had been teaching journalism in Iran.
The dual British-Iranian has been held in detention since April 2016.
Mr Ratcliffe hopes the latest meeting will expedite her release.
"We talked, of course, about the point of diplomatic protection ... and it's different from diplomatic immunity," he said.
He continued: "I said I thought it would be important and helpful. The Foreign Secretary and the Foreign Office expressed reservations, and we agreed that there are some questions that we have sent from the lawyers.
"They have agreed to answer the questions and then for the lawyers to sit down and talk it through. Both legally and then also practically.
"But certainly, I think it is an important thing for us to be pushing for."
Mr Ratcliffe expressed concern for his wife's state of health.
"She talks about being on the verge of a nervous breakdown. I absolutely believe that's true," he said.
"I think it's important I don't exaggerate anything in the media and I'm not melodramatic, but she is in a difficult place."
Ms Siddiq, who is Mrs Zaghari-Ratcliffe's MP, described the meeting as "encouraging".
Shesaid Mr Johnson had made clear he would "certainly" push to see Mrs Zaghari-Ratcliffe himself in prison if he goes to Iran.