Iran tried to recruit the British-Australian academic Kylie Moore-Gilbert as a spy for Tehran in exchange for her release, but the overture was furiously rebuffed, letters smuggled out of Evin prison reveal.

Moore-Gilbert, a Cambridge-educated academic specialising in Middle East politics, is currently being held in Ward 2A, an isolated Revolutionary Guard-run wing of Tehran’s notorious Evin prison, serving a 10-year sentence for espionage, a charge she, and the Australian government, rejects as entirely false.

In a series of handwritten letters to Iranian authorities seen by the Guardian, Moore-Gilbert alleges her detention is politicised, revealing that last October she was even shown two alternative decisions to her appeal: one for a 13-month sentence (essentially ‘time-served’ and which would have seen her released), another confirming the original sentence of 10 years.

She writes that she has little money to buy food, is denied phone calls to her family, and that her failing physical and mental condition has seen her repeatedly transferred to hospital.

Moore-Gilbert has categorically rejected overtures to spy for Iran.

In a letter to her “case manager”, Moore-Gilbert furiously writes “please accept this letter as an official and definitive rejection of your offer to me to work with the intelligence branch of the Iranian Revolutionary Guard Corps”.

“Under no circumstances will I be persuaded to change my decision.

“I am not a spy. I have never been a spy and I have no interest to work for a spying organisation in any country. When I leave Iran, I want to be a free woman and live a free life, not under the shadow of extortion and threats.”

A lecturer in Islamic Studies at Melbourne University, Moore-Gilbert has been imprisoned in Evin prison since September 2018, after she was arrested at Tehran airport while trying to leave the country after attending an academic conference.

Moore-Gilbert, who holds both British and Australian citizenship but was travelling on her Australian passport, was arrested by the intelligence arm of Iran’s Revolutionary Guard Corps, having been flagged as “suspicious” by a fellow academic and by a subject she interviewed for her research.

She was tried and convicted in secret last year on charges of espionage and sentenced to 10 years in prison. An appeal against her sentence failed.

In her letters from prison, spanning June 2019 to December 2019, Moore-Gilbert reveals an isolated and precarious existence. She spent months in solitary confinement, confined to a 2mx3m cell where the lights remained on 24 hours a day, and was blindfolded if she was ever moved.

In a letter dated 26 August, Moore-Gilbert begs with prison bosses to be moved from the isolated 2A section of Evin prison, run by the Revolutionary Guard, into the general female section of the prison, as demanded by Iranian law following her sentencing and the rejection of her appeal.

“I have been in 2A for almost a year and especially after my verdict, my health has deteriorated significantly. In the past month I have been to the special care at Baghiatallah Hospital twice and the prison infirmary six times.

“I think I am in the midst of a serious psychological problem, I can no longer stand the pressures of living in this extremely restrictive detention ward anymore. My situation here is even more difficult due to the ban on having any phone calls with my family. I worry a lot about their reactions to my verdict but I cannot talk to them. This is really inhumane.”

In her letters Moore-Gilbert is unerringly polite, thanking officials for their assistance in her case or for returning confiscated books – even apologising for her rudimentary Farsi – but she is adamant her conviction is false.

“I am an innocent woman,” she wrote to prison chiefs in August, “[and] have been imprisoned for a crime I have not committed and for which there is no real evidence.

“This is a grave injustice, but unfortunately it is not a surprise to me – from the very beginning [of my arrest] it was clear that there was fabrications and trumped-up accusations.” She signed off the letter “Professor of Melbourne University and an innocent political prisoner”.

Moore-Gilbert argues the capricious nature of her sentence was demonstrated by the fact that in November she was shown two different decisions to her appeal – one for a 13-month sentence (essentially time served and that would have seen her released), another confirming the original sentence of 10 years.

“How is it possible that two very different appeal decisions were delivered to ‘2A’ detention centre? It is clear that Iranian Revolutionary Guard Corps Intelligence is playing an awful game with me. I am an innocent victim.”

The Australian foreign minister, Marise Payne, met with her Iranian counterpart, Javad Zarif, on the sidelines of a global leadership conference in India this week. She says she pressed Moore-Gilbert’s case again with him.

“The government has been working extremely hard in relation to the ongoing detention of Kylie Moore-Gilbert,” Payne said. “We don’t accept the charges on which she has been held and are concerned for her protection and the conditions under which she is held.”

But the Iranian government has been firm on her conviction and sentence.

A spokesman for Iran’s foreign ministry, Abbas Mousavi, said last month that “Iran will not submit to political games and propaganda” in response to media reports of diplomatic pressure.

Moore-Gilbert was detained for “violating Iran’s national security”, Mousavi said. “Like any other individual with a sentence, [she] will serve her time while enjoying all legal rights.”

Moore-Gilbert’s most immediate concern is with her simple survival in prison. She has repeatedly written to authorities requesting better access to medication, and for money to buy food she can safely eat – she is allergic to much of the prison’s food – and personal items. She says she needs about A$70 (US$50) a month to survive.

“I am entirely alone in Iran. I have no friends or family here and in addition to all the pain I have endured here, I feel like I am abandoned and forgotten, that after so many times of asking my embassy, I still have no money at all to endure all of this.”

Sources with knowledge of Moore-Gilbert’s case argue the Australian government should be pushing more forcefully to have the academic – if she can’t be freed – moved from the isolation of Ward 2A to the general prison population.

But diplomatic progress on Moore-Gilbert’s case is complicated by the intense external and internal pressure the Iranian government faces at present, labouring under sanctions and with its relations with the west under acute strain.

Iran responded to the US assassination of its most powerful general, Qassem Suleimani, with missile strikes on US bases in Iraq earlier this month.

But in the hours after the strikes, on-alert Revolutionary Guards accidentally shot down a passenger plane in Tehran, killing 176 civilians, and sparking mass anti-government protests in the capital.

Australia has historically had a more resilient relationship with Iran than most of its western allies, but it is increasingly seen in Tehran through the prism of its staunch allegiance to the US. Canberra has, for now, fewer levers of influence to pull with Tehran.

Australia last week sent the warship HMAS Toowoomba to the Middle East as a contribution to the US-led coalition protecting oil tankers traversing the Strait of Hormuz, on Iran’s southern border.

Iran also wants to force western militaries from neighbouring Iraq – over which it seeks to impose greater influence – and Australia’s continued troop commitment to the US coalition there is a further complication in the relationship.

The Iranian citizen Negar Ghodskani, held in an Adelaide prison for two years on allegations of sanctions busting while she fought extradition to the US, was ultimately sent to America last year – to Iranian displeasure – where a judge sentenced her to time served and ordered her released. Ghodskani has since returned to Iran.

Two other Australians – the travel bloggers Jolie King and Mark Firkin – held for allegedly flying a drone near a military base in Tehran were released in October reportedly as part of an unacknowledged “prisoner swap” for the Iranian doctoral student Reza Dehbashi Kivi, who was imprisoned in Brisbane on sanctions-busting charges.

There are other Iranians in Australian custody on similar charges, but Canberra is anxious to avoid the impression of straight prisoner swaps. Tehran is less concerned about the optics of prisoner exchanges.

Up to five people with dual British-Iranian nationality, or with UK connections, are believed to be held in prisons in Iran, including Nazanin Zaghari-Ratcliffe and Anousheh Ashoori, also in Evin, and sentenced to five and 12 years in prison respectively. Families of detained Britons have said they are being held as collateral and that the heightened tensions have made it harder to secure their release.