Mrs Zaghari-Ratcliffe returned to the UK, and to her husband Richard and daughter Gabriella, on Friday morning after the UK paid an almost £400million debt to Iran.
In an impassioned statement during the press conference, she criticised previous foreign secretaries for their lack of action in securing her return to the UK.
Although her husband praised Liz Truss for bringing his wife back home, Mrs Zaghari-Ratcliffe, 43, said her release “should’ve happened six years ago”.
“I grant what Richard said to thank the foreign secretary, I do not really agree with him on that level.
“I have seen five foreign secretaries changed over the course of six years. That is unprecedented given the politics of the UK.
“I love you, Richard. I respect you but I was told many, many times that, ‘oh, we’re going to get you home’. That never happened.
“So there was a time that I felt like, you know what, I’m not going to trust you because I’ve been told many, many times that I’m going to be taken home.
“But that never happened. I mean, how many former secretaries does it take for someone to come out? Five? It should have been one.”
Mrs Zaghari-Ratcliffe said her family had been through a tough journey and there was a lot to catch up on after being away for so long.
Beginning the press conference, Tulip Siddiq, Labour MP for Hampstead and Kilburn, said she had called on the Commons Foreign Affairs Committee to look into her ordeal and in particular, why Britain’s debt to Iran for military equipment could not have been settled sooner.
“I feel Nazanin could have been home a long time ago if we had paid the historic debt of £400 million earlier,” Ms Siddiq said.
Mr Ratcliffe did say he was “glad to be retiring” as a campaigner for his wife after such a long time away from each other.
“We’re still negotiating whether daddy is allowed to sleep in the same bed as garbiella and Nazanin but we’ll get there,” Mr Ratcliffe joked.
“But this is my retirement day, and I’m glad it has come.”
Fellow British national, Anoosheh Ashoori also returned to the UK after being detained in Iran last week.
A second man, Morad Tahbaz, who holds UK and US nationality, was released from prison but is not yet allowed to leave Iran. His daughter was at the press conference.
The Government has said it is working to secure the release of Mr Tahbaz.