Speaking from his family home, Mr Ratcliffe said that the memory of his wife Nazanin sitting on the sofa at home with a cup of tea while he played with their daughter is what helped her get through eight months in solitary confinement.
He said that he does not focus on that particular moment but that when he thinks about what it would be like to have them back he imagines “having them home and having the toys all moved around again, tidying them up and treading on Lego - all those kind of things that are just the bustle of normal life, rather than an empty house that is staying in the same way it was."
In April 2016 Mrs Zaghari-Ratcliffe, 38, was arrested when trying to leave Tehran with her young daughter Gabriella.
She was accused of plotting to topple the regime and sentenced to five years in prison. She denies all the charges.
Currently she has spent 20 months in prison, while her daughter stays with her Grandparents in Tehran.
Mr Ratcliffe described his current way of life as “temporary living” and that he is keeping the house the same as he thinks it is important for his wife and child to return to familiar surroundings.
The family home in West Hampstead remains almost untouched from how it was when his wife and daughter were last in it, he added.
He spoke about the strain the time away has had on his relationship with his daughter, who he communicates with over Skype.
"Inevitably as her English faded and she learnt Farsi, our relationship has been restrained," he said.
Mr Ratcliffe also spoke of the toll the time in prison has taken on his wife whom he speaks to over the phone.
He described how his wife has admitted to him a number of times that she is on the brink of a “nervous breakdown”.
He said that her first few weeks in prison were the hardest for his her and that she still will not talk about it.
The family had hoped that she would be home by Christmas and that they chose the date because it is “something to look forward to, it is such a nice time having the family together and of course she is eligible for early release around there, (plus) it is her birthday as well."
The campaign for Mrs Zaghari-Ratcliffe’s release has gained a lot of attention in recent weeks after Boris Johnson falsely claimed that she had been in Iran training journalists.
Campaigners say that Mr Johnson's mistake could lead to Mrs Zaghari-Ratcliffe facing an increased prison sentence.
Mr Johnson has since apologised for his remarks and he said that he will go out to Iran before the end of the year.
Mr Ratcliffe said: "Now when I get on the train, people recognise me and wish me well. That is really important to me, it really matters.
"Now we are in a different place, yes, it is really stressful for me, it is very stressful for Nazanin, but hopefully it will lead us to a happy conclusion."