"I don't differentiate between medicine and politics. They're connected," said Ruchama Marton, founder of Physicians for Human Rights-Israel (PHR-I). "More than connected: They're inseparable."

At the time of this 2013 interview, she was speaking about the "endemic medical negligence" that Palestinian political prisoners face in Israeli jails.

That fact has not changed, and is one of the key reasons why more than 1,000 Palestinian prisoners launched one of the largest collective hunger strikes in recent years on April 17.

The doctors who work within the Israel Prison Service (IPS) are at the heart of the problem. Most have minimal medical qualifications, Marton noted - but more importantly, they are employed by and answerable to the IPS rather than the Ministry of Health.

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Critics argue that this creates professional and ethical conflicts of interest. Sahar Francis, director of the Addameer prisoners' rights group, noted: "In this hierarchy, the doctors are under the head of the prison authority, so their reliability is not for medical ethics but for the prison system."

The Israel Medical Association and human rights organisations including PHR-I have been campaigning for the state to transfer responsibility for prisoners' health to the health or justice ministries, but experts say it seems unlikely that Israel - which has not formally responded to the request - will comply.

"The prison authorities, having their doctors under control; it's a power position. They don't want to lose it," Marton said.

Palestinian prisoners may have existing medical conditions at the time of arrest or they may develop conditions and diseases during their imprisonment, often owing to poor conditions, according to Addameer. Rights groups also cite significant obstacles to prisoners receiving the medical care they require in jail.

While each prison has a medical clinic, delays are endemic and the general outcome is a prescription for basic painkillers, observers say. Access to a specialist is particularly difficult and rife with delays, leading to potentially serious complications.

The most difficult moments are when you feel that you are suffocating, to pass into unconsciousness and reawaken to feel like you're in another world. You lose consciousness and regain it, and you fear that next time that won't happen. Mohammed al-Taj, former prisoner

"For a prisoner to get a good medical examination and diagnosis is very hard," Marton said. "And then to get the right treatment after getting the right diagnosis is even harder. Prisoners can complain for a very long period of time before a doctor will see them; then, it's not guaranteed that the doctor will really examine and give them the right diagnosis."

Language barriers and the power relationship between prison doctor and prisoner means that there is no trust, an essential element from a patient's point of view.

In addition, access to patients inside prisons by independent Israeli and Palestinian doctors is fraught with difficulties. Rasha Abbas, a legal researcher at Addameer, noted that her organisation has been unable to get permission from the IPS to visit hunger-striking prisoners whose health is deteriorating.

Marton said that PHR-I doctors face a protracted, arbitrary, costly and bureaucratic process that makes it extremely difficult to get permits to prisons to independently assess the health of Palestinian patients.

The case of Mohammed al-Taj, a former political prisoner granted early release in 2013, illustrates the Kafkaesque system. He was diagnosed with pulmonary fibrosis and required a double lung transplant. His ability to speak was laboured and he required oxygen every few minutes.

Taj said that in 2004, he began experiencing breathing difficulties after he and other prisoners were beaten and exposed to nerve gas in prison. He said that he kept trying to be seen by the prison doctors for years as his health deteriorated, but received no examination or appropriate treatment for it.

In 2010, he was finally taken for a CT scan, only to be told that the test results were lost. In 2012, he embarked on a hunger strike to fight for his medical rights. He was eventually given an early release after serving 10 years of a 15-year sentence, and believed at the time that he was released early because his chances of surviving were slim and because Israel "didn't want to pay for the lung transplants".

Nearly three years later, after receiving several rounds of treatment in Austria, the funding for his care from the Palestinian Authority ran out and his condition swiftly deteriorated; he could speak only with his oxygen mask on, and as he spoke, he struggled to breathe and to remain focused. He was fully dependent on his elderly mother and his wife to help him with everyday tasks, and he lost consciousness frequently.

"The most difficult moments are when you feel that you are suffocating, to pass into unconsciousness and reawaken to feel like you're in another world," Taj said. "You lose consciousness and regain it, and you fear that next time that won't happen."

Taj is relatively fortunate - he managed to survive long enough to undergo a heart and lung transplant operation in India in 2015. Each year, however, there are typically several cases of prisoners and former prisoners whose deaths are attributed to medical negligence. Last week, Mazen Muhammad al-Mughrabi, 45, died of kidney failure after complications that went untreated while he was in prison, according to the Palestinian Committee of Prisoner Affairs.

For patients with mental health conditions - both those present at the time of arrest and those that develop as a result of treatment in prison, including torture and solitary confinement - the situation is even bleaker. Instead of getting proper treatment in a psychiatric hospital, they are often held in solitary confinement, exacerbating their condition.

In a 2016 report, PHR-I noted that "holding prisoners in solitary confinement due to their mental health state is illegal". The group also cited a report prepared by the Israeli State Comptroller that "severely criticized the conduct of the IPS's mental health system and the huge discrepancy between prisoners' mental-health needs and the deficient, low-quality services provided in reality".

Meanwhile, as the the health of the prisoners currently on hunger strike deteriorates, the medical ethics issues facing Israeli doctors within the IPS - including issues around torture, medical negligence and force-feeding of hunger strikers - are being highlighted once again.

William Parry previously worked as a communications and advocacy officer for Medical Aid for Palestinians, a UK-based NGO.