A north London mother who has been detained for more than 100 days in Iran is so weak she can barely walk and is losing her hair, according to an appeal for her release.
Nazanin Zaghari-Ratcliffe has been held by Iran's Revolutionary Guard for over three months, having to endure solitary confinement and being separated from her young daughter and husband.
A letter to Foreign Secretary Boris Johnson claims conditions in the jail have led to extreme weight loss and severe deterioration of her health, leaving her struggling to walk.
The letter, written on behalf of her husband Richard Ratcliffe urged Mr Johnson to take on this "harrowing and urgent matter".
The charity worker, from West Hampstead, has been accused by the IRG of participating in the "design and implementation of cyber and media projects to cause the soft toppling of the Islamic Republic" - an accusation her husband branded "crazy".
Mrs Zaghari-Ratcliffe, who has duel Iranian-English citizenship, was arrested in April whilst travelling with her two-year-old daughter Gabriella to visit family.
Gabriella, had her passport confiscated at Imam Khomeini airport and is being looked after in Iran by her grandparents who speak little English.
She turned two in June and spent her birthday without either of her parents.
Mr Ratcliff has been unable to see either of them for the last three months.
His letter to Mr Johnson reads: "We appreciate that you have just taken over the role as Foreign Secretary and will be facing many competing pressing demands.
"But the plight of Nazanin is of utmost urgency and cannot continue to be ignored.
“She has been subjected to the harshest of injustice, and it is critical that she now receives the full immediate support and attention from the highest levels of Government.
"We ask you to do all in your power to secure the freedom of this entirely innocent and increasingly frail and desperate young woman, who is a citizen of London with (dual) British nationality, and to bring her and her two-year old British daughter back to England."
Mr Ratcliffe previously claimed his wife was being held as a "bargaining chip", after Iranian officials said they are holding her to pressure the UK government into an agreement and would close her case if this was reached.
He previously delivered letters to David Cameron and Theresa May before the latter took over as Prime Minister.
Nearly 800,000 people have signed a Change.org petition in support.
Speaking about his last telephone conversation with Ms Zaghari-Ratcliffe around a month ago, Mr Ratcliffe said: "She was just really sad and it was quite emotional: she cried and I cried.
“She said she was exhausted about how long it had gone on for and just 'please do what I could'."
It will be their seventh wedding anniversary on August 14 which is traditionally associated with wool and Mr Ratcliffe plans to highlight his separation from his wife by attaching a padlock and knotted wool to a London bridge.
He said there had been some positive signals recently but he had "learnt not to get his hopes up too much".
Earlier in July, the Foreign Office updated its advice warning dual Iranian-British citizens that there was a risk of their being "arbitrarily detained" in Iran, and noting "serious concerns that the subsequent judicial process falls below international standards".