For 70 days, Shabnam Madadzadeh lived alone in a cell measuring roughly three metres by two.

The room contained almost nothing apart from three blankets, a thin carpet and a searing fluorescent light overhead that never switched off.

Her watch had been confiscated when she arrived, along with every personal belonging she carried, leaving her with no way to tell whether it was day or night.

But the silence rarely lasted long enough to become comforting, as from elsewhere inside Section 209 of Evin Prison, Madadzadeh could hear women screaming from beatings and rape.

'You hear people screaming, crying, begging. Sometimes you imagine the voices are your family members. You think maybe it is your brother or your sister. They want you to hear it and they want you to break,' she recounts.

Then, the door would inevitably open, signalling her turn. 'We can do anything to you and nobody will hear your voice,' the interrogators told her as they began to beat her.

Madadzadeh was 21 years old when she was arrested in Tehran in 2009 and sentenced to five years in prison for opposing the regime.

At the time, she was studying computer science at university and had become involved in Iran's student protest movement during the presidency of Mahmoud Ahmadinejad.

More than a decade after her release from Iran's brutal detention centre, 38-year-old Madadzadeh still cannot shake the horrors she witnessed during her time in prison, as she shares her detailed account with the Daily Mail.

On the day of her arrest, she was travelling by taxi to meet other activists when intelligence officers stopped the vehicle.

'They did not show identification or explain anything,' she says. 'At first, I didn't even understand I was being arrested - it felt like a kidnapping.'

The officers initially told her she was being detained over minor infractions, suggesting it might be related to dress code violations.

It was only later, after she was transferred into the intelligence wing of Evin Prison, that she understood the true reason for her arrest.

'I was taken to Section 209 of Evin Prison, which is controlled by the intelligence services. It's a very notorious place, with many solitary confinement cells. It's where they hold people accused of political activities,' she says.

Madadzadeh says intelligence officers demanded she confess to links with the MEK, the exiled opposition movement formally known as the Mujahedin-e Khalq, because some of her relatives were associated with the organisation.

Interrogators wanted her to denounce the group publicly and participate in a televised confession.

'They wanted me to say whatever they told me to say,' she recalls. 'They wanted forced confessions.'

When she refused, she was severely beaten with sticks, chairs and whips. During interrogations, she was blindfolded and forced to face the wall while up to six guards would surround her and carry out the violent assault.

The guards threatened to rape her, taunting that nobody would hear her screams.

One of the most traumatic moments of her imprisonment came during an interrogation involving her brother, who had been arrested alongside her.

One day, guards ordered Madadzadeh to remove her blindfold. Her brother was standing in front of her surrounded by interrogators.

'They forced me to look as they began beating him in front of me,' she says.

'They wanted him to make a false confession and they wanted him to convince me to make one too.'

She says interrogators threatened to execute both of them, saying they would execute her brother first as she watched. 'You will see him for the last time,' they taunted her.

After that, she stopped sleeping. 'Every night I stayed awake waiting for them to come,' she says. 'I wanted to be awake if they came to take me to my execution.'

The constant mental torture was worse than the beatings, she said, as the men would routinely threaten to arrest and torture other members of her family.

'They told me my parents and friends were already in custody. They said nobody knew where I was and nobody would help me.'

Madadzadeh says she heard repeated accounts from other prisoners who described being raped during interrogations, particularly women held on ordinary criminal charges who lacked outside visibility or political support.

'For ordinary prisoners, nobody hears their voice,' she says. 'Many of them were poor women with nobody protecting them.'

One woman she met had been repeatedly raped during interrogations until she signed a confession.

'She was a mother of two children,' Madadzadeh says. 'She refused to confess at first. But after repeated rape and torture, she finally confessed.'

Inside solitary confinement, she developed routines to maintain her sanity, such as exercise, mentally repeating university lessons and reciting songs to herself because she was denied books, pens and paper.

'I tried to keep my mind active,' she says. 'Because if you lose your mind there, you lose everything.'

She also scratched marks into the walls to count the days she was held in the cell. 'You lose your sense of reality very quickly,' she says.

Madadzadeh also found solace in the memory of those who had survived before her, taking comfort in a cell-wall inscription left by a prominent prisoner.

'It is a custom in these prisons for previous inmates to write something on the wall,' she explained. 'When I entered the cell, I saw the name Saeed Masouri written. Seeing his name gave me strength.'

'It reminded me that I'm not the first to experience this imprisonment and I won't be the last, so long as this regime still stands.'

Masouri, who is Iran's longest-serving political prisoner, has been on death row for over 25 years.

Madadzadeh left her own message on the wall, inscribing a verse by 14th-century Persian poet Hafiz Shirazi.

'The earth and the skies could not keep this trust of the clock. Yet the poor insane me was stuck with such tough luck,' the verse reads.

After 70 days in solitary confinement, she was formally sentenced to five years and transferred between several prisons, including Gohardasht in Karaj and Qarchak Prison in Varamin, where she says conditions deteriorated further.

'The situation in Qarchak was worse than anywhere else,' she says. 'The water was not drinkable. Even washing clothes with it damaged them almost immediately.'

Food was rotten and inedible, prisoners would get sick constantly and were severely malnourished.

'We practically never had meat,' she says. 'Mostly rice and watery stew.'

Basic items had to be purchased from prison shops at inflated prices, leaving poorer inmates dependent on inadequate prison supplies.

'Sometimes there was canned tuna in the shop, maybe once a month,' she says. 'But many prisoners could not afford it.'

Meanwhile, medical care inside the prison was nonexistent, and withholding life-saving treatment was another deliberate form of punishment used against inmates.

'We didn't bring you here to to pamper you. We brought you here to torture you,' the prison doctor would say when inmates begged for treatment. 

'There were prisoners who died because they did not receive care,' she says, 'Authorities refused to transfer them to hospitals.'

Despite constant surveillance, Madadzadeh began secretly documenting what she witnessed inside the prison system. 

She smuggled letters and testimony outside through phone calls and family visits. 

Some of these stories later reached international organisations and human rights groups, including Amnesty International, which mentioned her case in reports on Iran. 

Among the women she met in prison was Shirin Alam-Holi, a Kurdish political prisoner who became one of her closest friends after they were held in the same cell together. 

Alam-Holi had not been able to finish her education before prison, so other inmates would gather together and teach her history, geography and other subjects.

Alam-Holi hoped to pass her exams in the future, but that dream was quickly shattered when she was sentenced to death.

'I told her it wouldn't happen,' Madadzadeh says, 'I told her that people outside would work to stop her execution.'

'We made plans for the future, imagining that after we were released we would travel, go to the mountains near Tabriz, and live freely.

'She also spoke Turkish, my mother tongue, so we would sing songs together.'

One night, guards came for Alam-Holi, claiming there was an issue with paperwork in her case.

'They closed all the prison doors after they took her,' Madadzadeh says. 'We understood something was wrong.'

Madadzadeh waited all night for her to return, but she never came back.

That morning, on May 9, 2010, Alam-Holi was executed by hanging alongside four other prisoners. 

After surviving five years of abuse, interrogation and dismal conditions in Iran's most notorious detention centers, Madadzadeh was finally freed.

Her release, she says, was bittersweet. 'It was very difficult. Leaving prison meant leaving behind so many people I cared about. I remember seeing the families of other prisoners, especially children whose mothers were still inside. That was very hard.'

At the same time, she says she felt a heavy responsibility to continue to speak out against the injustices of the regime - the consequences of which she knew all too well. 

'At first, I stayed in Iran and tried to continue my studies and activism. But I was constantly monitored. They would call me and remind me they knew what I was doing,' she says.

'I felt like I had left prison and entered a new kind of prison. I realised I couldn’t continue like that, so I left Iran. I didn’t leave for a better life, but to continue my work and speak about what I had seen.'

Madadzadeh now lives in Switzerland where she works with organisations including the United Nations to raise awareness about the human rights abuses inside Iran.

She has barely any contact with her family still inside the country, as they were previously harassed and interrogated for speaking to her.

'It's a sacrifice I'm willing to make,' she says, 'When I left Iran, it wasn’t for personal freedom or comfort. It was a commitment to continue this work.'

Amid a tense, deadlocked conflict where Iranian civilians bear the brunt of airstrikes and threats, I asked Madadzadeh whether a domestic revolution is possible, or if Trump's bombs are the only way to depose the regime.

'People are suffering, no one wants their country to be bombed. That idea is not real. People want change, but not through destruction of their own country,' she told me.

'Nothing happened over the past few months. Some key figures were killed but the regime stands strong. I believe true change will come from inside Iran, from the people and from organised resistance.'

Madadzadeh calls on the international community to step up in condemning the relentless executions, arrests and internet blackouts in Iran.

'Governments should do more than issue statements - they should take real action to pressure the regime, including economic and diplomatic measures, to stop executions and human rights abuses.

'They can do a lot more. They can shut down the embassies and cut off their deals with the regime. They should include human rights issues in negotiations.

'There are so many political prisoners currently at risk of execution. Some are very young. We don’t even know all their names.

'I ask people to speak about them, to raise awareness, because that can help save lives.'