Nazanin Zaghari-Ratcliffe is being used as a "political pawn" and the UK must not process any Iranian funds until she is released, a Nobel laureate has said.
Monday marks the British-Iranian charity worker's 800th day in jail having been accused of spying.
It also marks her four-year-old daughter Gabriella's fourth birthday and 800 days since she was separated from her parents.
Ms Zaghari-Ratcliffe, who is already serving a five-year prison sentence, is facing a further hearing accused of an unspecified security charge.
Her husband, Richard Ratcliffe, believes his wife, from Hampstead, north London, is likely to be facing an allegation of spreading propaganda against Tehran's Islamist regime.
Shirin Ebadi, an Iranian human rights lawyer, former judge and human rights activist, who won the Nobel Peace Prize in 2003 for her efforts to promote democracy and human rights, called for the mother-of-one to be released.
She said: "Yes, Nazanin Zaghari-Ratcliffe is being used as a political pawn but it is not just her.
"There are currently over 30 dual nationals that are being held in Iran, so pressure must be put on the Iranian government in that regard.
"Any trade agreements must be conditional on the release of these dual nationals."
Dr Ebadi, who sits on the selection committee for the Aurora Prize for Awakening Humanity, which was awarded on Sunday to Rohingya activist Kyaw Hla Aung, was speaking at the event in Armenia.
She added: "In the first place the UK should downgrade its political relations with Iran until they free not only Zaghari-Ratcliffe but other dual-Iranian nationals held in prison.
"The British Government must not allow its banks and companies to sign any deals or process any Iranian funds until they are released."
Mrs Zaghari-Ratcliffe was arrested and jailed in 2016.
She has consistently denied all allegations, insisting she was on holiday to introduce her daughter to her family.