This week, the British royal family is rolling out the red carpet to greet hundreds of guests from around the world at the annual Royal Windsor Horse Show, which began on Wednesday and continues until Sunday. It is a major part of the royal calendar, with the Queen in attendance. Among the most enthusiastic of the show’s regular guests is King Hamad bin Isa al-Khalifa of Bahrain, who is invited every year to enjoy the opulent equestrian festivities, and his sons.

Hamad enjoys friendly relations with the Queen. In 2013, he gifted her two prized Arabian horses from his royal stables. In 2017, the Queen returned the gesture, presenting him with a horse from her own stables. Hamad even has an event at the show – Saturday’s King’s Cup – named after him.

The torture was so severe that he required four operations, and continues to suffer from his injuries to this day

Yet while the king socialises with dignitaries, my ageing father languishes in a cell in Bahrain, denied access to medical treatment for a range of serious illnesses. He is not alone: thousands of political prisoners fill the overcrowded cells of Bahrain’s prisons, and many others are deliberately denied medical care.

In Bahrain, Hamad rules with an iron fist. Since 2011, when a huge number took to the streets to demand the fall of the centuries-old al-Khalifa dictatorship, he has overseen a violent crackdown. All political opposition has been outlawed. A nation of 1.5 million citizens now has the highest prison population rate in the Arab world. Just this week, Bahrain upheld death sentences for two torture victims, who will be executed at the discretion of the king.

My father, Hassan Mushaima, is a victim of this repression. As the leader of a major opposition party, he is a lifelong campaigner for democracy and a well-respected figure in Bahrain. However, his leading role in the anti-government protests of 2011 saw him and many other opposition leaders arrested, tortured and jailed for life by military tribunal.

Ali Mushaima (@AMushaima) Today, I resumed my protest to save my 71 year old father #FreeHassanMushaima, who is still denied medical care.



This time, I protest against the person who’s responsible for my father’s imprisonment.



Dictator Hamad of #Bahrain is at @windsorhorse & will sit next to the Queen. pic.twitter.com/9rH8xAlqHl

Bahraini authorities are killing my father, I’m on hunger strike to save him | Ali Mushaima Read more

At 71 years old, my father is an elderly man with a series of complex health problems. He requires regular check-ups to monitor for the resurgence of lymphatic cancer. He also has diabetes and prostate issues, as well as problems with his ears stemming from the torture he was subjected to when he was arrested. The torture was so severe that he required four different operations, and continues to suffer from his injuries to this day.

However, time and again, the regime has refused to provide him an adequate standard of care. They have routinely cancelled or failed to schedule appointments with specialists, denied him family visits and even the right to books and religious texts. Human rights groups, including Amnesty International, have condemned his cruel and humiliating treatment and called for his release.

Last year, after hundreds of constituents contacted their representatives in support of my father, 15 MPs wrote to the Foreign Office asking them to press Bahrain to end his mistreatment. Despite the gravity of the situation, the Foreign Office refused to meet me, relying on false assurances from the Bahraini embassy in London to justify ignoring me.

Outraged at my father’s condition, I started a hunger strike outside the Bahraini embassy. In my desperation, I even wrote to the Queen, imploring her to intervene on my father’s behalf. After 46 days, during which I lost 16kg (2.5 stone), I was advised by doctors to abandon my hunger strike. This is what it took for Bahrain eventually to take my father to his appointments and permit his family to visit him in prison.

Now the regime is again denying my father access to medical specialists. Authorities at Jau prison refuse to bring him to appointments unless he submits to being strip-searched, shackled and taken to the hospital in chains. My father is sick and elderly, and poses no escape risk – these measures have been introduced purely to humiliate him, and he refuses to submit to such demeaning treatment.

The UK’s repeated failure to condemn abuses in Bahrain has only emboldened its leaders. In 2017, Bahrain detained family members of activists protesting in the UK and sent thugs apparently affiliated with the security services to harass the demonstrators.

I will do anything to save my father’s life. I want to show everybody that the British government is turning a blind eye to his slow murder. This week, which marks the first week of Ramadan, Hamad is in the UK for the Royal Windsor Horse Show. I am observing the fast outside in protest, to demand Bahrain end its abhorrent treatment of my father. British complicity with human rights abuses in Bahrain must end now.

• Ali Mushaima, a political activist based in London, is the son of the jailed Bahraini opposition leader, Hassan Mushaima