Nazanin Zaghari-Ratcliffe remains in jail only due to a financial row between Iran and the UK, campaigners have claimed.
The Free Nazanin campaign claims that Mrs Zaghari-Ratcliffe, who was arrested in Tehran in 2016, was taken to meet the judiciary on Wednesday and told that her ongoing imprisonment was due to a “continuing dispute” between the two countries over the interest rate used to calculate the present value of historic debt.
Last year Sky News revealed that the UK Government was trying to find ways to release the £450m sum owed for a cancelled arms deal in the 1970s, although the Prime Minister’s spokesperson denied the move had anything to do with the case to free the 39-year-old.
The Iranian deputy foreign minister is due to speak at Chatham House on Thursday, and campaigners have called on him to “clarify what stones still need to be unturned in Nazanin’s case”.
Her husband Richard Ratcliffe told Sky News: “It’s just a question of agreeing whether it’s 3% or 4% or whatever the number is to be used.
“Once that’s agreed and everything else is in place, then as far as I understand Nazanin can come home.”
The Foreign Office has denied the claims, insisting that her case was not linked to the debt issue.
A spokesman said: “This is a longstanding case and relates to contracts signed over 40 years ago with the pre-revolution Iranian regime.
“We and the Iranians reject any idea the two issues are linked.
“Funding to settle the debt was paid to the High Court by the Treasury and the International Military Services in 2002.
“Iran’s Ministry of Defence remains subject to EU sanctions.”
Mrs Zaghari-Ratcliffe is serving a five-year sentence over allegations – which she denies – of planning to topple Iran’s government.
Foreign Secretary Boris Johnson has repeatedly lobbied Iran over the case of the detained British-Iranian.
In December, Mr Ratcliffe suggested his wife was “close” to returning home after she was made eligible for early release, but saw his hopes of her leaving jail in time for Christmas dashed.