The UK Foreign and Commonwealth Development Office urged Iran to release all of its detained British nationals during talks with a high-level delegation in London on Thursday.
The talks were led by James Cleverly, the UK's Minister of State for Middle East and North Africa, who met Iran's deputy foreign minister Ali Bagheri Kani in Whitehall.
In a statement, the FCDO said it had “pressed” Iran to urgently release UK nationals who had been unfairly detained, including Nazanin Zaghari-Ratcliffe, Anoosheh Ashoori and Morad Tahbaz.
“The Foreign Secretary, Minister Cleverly and the FCDO continue to work hard to secure the release of all those British nationals unfairly detained in Iran”, the spokesman added.
Mr Cleverly also met Richard Ratcliffe and reaffirmed the government's commitment to reuniting his wife, Ms Zaghari-Ratcliffe, with her family.
But Mr Radcliffe described the meeting with Mr Cleverly as “depressing” after telling him he was coming away from it with “no hope”.
Mr Ratcliffe has endured his 19th day on hunger strike outside the FCDO building in central London.
He began his demonstration last month after his wife lost her latest appeal in Iran, saying his family is “caught in a dispute between two states”.
Speaking to reporters after his meeting with Mr Cleverly, Mr Ratcliffe said: “If I’m honest, quite a depressing meeting.
“In terms of what we got told, well, not much.”
He said Mr Cleverly wanted to emphasise that the meeting with the Iranian delegation had been “cordial”.
Mr Ratcliffe added: “He’d raised Nazanin’s case, the case of the others (detainees). He said that was a good step. Couldn’t give a timeline on when things were going to move forwards.”
He told reporters he would continue his hunger strike outside the FCDO “this evening”, but said he was nearing the end of it “as a strategy”.
Asked if he was going to carry on, Mr Ratcliffe said: “For this evening, yes.
“I think there’s a basic medical limit on how long you do a hunger strike for.
“I made a promise to Nazanin, I made a promise to my family, mum in particular, and to the family doctors, that I won’t take it too far.
“But yeah, I don’t think we walk away head held high feeling like it’s all been sorted.”
Asked how he would break the news to his daughter, Gabriella, he said: “Well, she probably doesn’t think in terms of ministerial meetings, she’s just asked when mummy’s coming home.
“I’m a little bit more deflated today than I was this time yesterday.”
Mr Ratcliffe said his family is “stuck in the same status quo” after the meeting.
“If I’m honest, it felt like, you know, perfectly nice, sincere, caring, everyone in the room was caring.
“But you know we’re still stuck in the same status quo. We’re still stuck in the same problems that led us to end up on hunger strike.
“I don’t feel they’ve given a clear enough message to Iran that hostage-taking is wrong. I don’t think there are any consequences to Iran at present for its continuing taking hostages of British citizens and using them.
“There was acknowledgement that clearly Nazanin is being held as leverage. No readiness to change course,” he said.
Mr Ratcliffe said he was “pretty irritable” in the meeting.
“I said to him (Mr Cleverly) at the end, ‘I come away with no hope. I felt that in your strategy it’s all carrots to Iran. There’s no stick’.
“I can’t see what’s stopping them from continuing to play games with Nazanin.
“I think by being here, Nazanin is probably safe for a few weeks. But what’s to stop them threatening to put her in prison again?”
Ms Zaghari-Ratcliffe, a British-Iranian dual national, has been in custody in Iran since 2016 after being accused of plotting to overthrow the government.
She was taking the couple’s daughter, Gabriella, to see her family when she was arrested and sentenced to five years in jail, spending four years in Evin Prison and one under house arrest.
According to her family, she was told by Iranian authorities that she was being detained because of the UK’s failure to pay an outstanding £400 million debt to Iran.
Mr Ratcliffe said the government would not talk about the debt to Iran. He said: “We asked about the debt and they wouldn’t talk about it, I mean really clammed up.
“He (Mr Cleverly) said ‘our position is well known’, and we said ‘well, look, frankly it’s not well known, you haven’t told us. I don’t know if you’ve told anyone else but we’ve never heard it’.”
Mr Ratcliffe told reporters: “I had hoped there would have been some kind of a breakthrough and recognition in the meeting with Iran — maybe that will be happening away from us, but I don’t have any hopes.”
Asked how he would give the news to his wife, he said: “I will probably wait a few hours and calm down.
“I think probably my expectations were higher than hers.”
He added: “I think things either move forwards or they move backwards. I don’t feel they moved forwards today. It may be that there are parts of the conversation I am not privy to and there are parts the minister shares down the line.”