LONDON (Reuters) - Bahraini opposition leader Hassan Mushaima is being denied vital medical care in jail in the Gulf state, says his son Ali Mushaima, on hunger strike outside Bahrain’s London embassy.

Hassan Mushaima, 70, was arrested in 2011 along with other Shi’ite activists and opposition figures and sentenced to life in prison for leading anti-government protests that year at the height of the region’s “Arab Spring” uprisings.

Amnesty International on Monday also accused Bahraini authorities of failing to provide proper medical care for Mushaima and three other elderly jailed activists for over a year.

“They are killing my father slowly, because when you are denying a 70-year-old man his medicine, his body will not take it,” said Ali Mushaima, sitting on a thin mattress on the pavement in front of the Bahrain Embassy, where he began his vigil on August 1.

Mushaima said his father had been treated for cancer several years ago, and needed regular check-ups to ensure the disease had not returned.

He said his father also suffered from high blood pressure, diabetes and a urinary tract infection. His medication is running out and authorities had not supplied him with new pills, Ali said.

Bahraini officials did not immediately respond to a Reuters request for comment. The Bahraini embassy in London last week denied Mushaima was being mistreated, saying he had been to the prison medical clinic 16 times since the beginning of 2018.

The embassy said “he continues to receive medical attention, along with his prescribed medications and a special diet as part of his medical regime.”

The embassy said Mushaima had been diagnosed with cancer 10 years ago. Since his conviction in 2012, arrangements had been made for scans every six months, it said.

“However, Mr Mushaima refused to attend these scans on both occasions last year,” it said on its Twitter account.

His son told Reuters: “They want to humiliate my father by putting handcuffs and shackles on his hands and feet, and he is saying I am not going to hospital or to see my family like this.”

SHI’ITE MAJORITY, SUNNI RULERS

Western-allied Bahrain, where the U.S. Fifth Fleet is based, crushed mass protests by the Shi’ite Muslim majority in 2011. The ruling Sunni Al Khalifa family has kept a lid on unrest since then by closing Shi’ite-led opposition groups and prosecuting activists.

Bahrain’s rulers have refused to make power-sharing concessions to the Shi’ites, seen by the authorities and Sunni Arab neighbors including Saudi Arabia as proxies for non-Arab Shi’ite rival Iran.

Authorities in Bahrain have convicted scores of people of terrorism in a series of mass trials. Rights activists say they are mostly peaceful opposition activists.

“The Bahraini authorities’ treatment of these wrongfully imprisoned peaceful activists violates international law and standards on prisoner treatment and constitutes cruel, inhuman and degrading treatment or punishment,” said Lynn Maalouf, Middle East Research Director at Amnesty International.

Demonstrators have clashed frequently with security forces, who have been targeted by bomb attacks. Bahrain has accused the opposition of undermining security and blamed the bombings on Iran and Lebanon’s armed Shi’ite group Hezbollah. Iran and Hezbollah deny any involvement in Bahrain’s unrest.

Ali Mushaima has been in London since 2006. He said he had been sentenced by Bahrain courts in absentia to 45 years in jail and his citizenship had been revoked.

He told Reuters that he began his hunger strike last week to raise awareness of his father’s plight.

“I have lost five kilos. I am drinking, but I am not eating. My demand is very simple ... I am talking about medical care, family visits and access to books.”

He criticized the U.S. and British governments for not pressuring Bahrain over the crackdown, saying the British government was “indirectly” responsible since it “trained the Bahraini police officers and provided technical assistance”.

A spokesperson for Britain’s Foreign and Commonwealth Office told Reuters on Monday: “We believe that only by working with Bahrain can we hope to bring about the changes we would like to see.”

Britain opened a permanent military base in Bahrain in April in an attempt to boost its role as a major player in the region.