Shaker Aamer, along with fellow detainees Nabil Hadjarab, Ahmed Belbacha and Abu Wa’el Dhiab, have filed a motion in US federal court in Washington DC, to stop them being force-fed and force-medicated.
The motion was filed by British legal charity, Reprieve, which is representing the men along with co-counsel Jon B Eisenberg.
It asks that the court rule to stop force-feeding in the prison and stop force-medicating prisoners, particularly with Reglan, a drug used by the US during the force-feeding process that when used for extended periods of time can cause severe neurological disorders, including one that mimics Parkinson’s disease.
Aamer is not currently being force-fed, though he has been in the past, but has begun taking small amount of nutrition in order to ward off force-feeding.
"On February 15th, when I started the hunger strike, I was 208lbs. Now I am maybe 150lbs," Aamer said in his statement.
"A lot of people are really in trouble now, the strike has gone on so long. Some people are just skin and bones. It’s not like the hunger strikes in 2005 any more; now, we’ve been through so much that the damage to our minds and bodies will be worse. I get very dizzy in the shower now. I am not what I used to be. I feel old inside."
Belbacha, who is currently being force-fed, said in the motion: “I am participating in this hunger strike of my own free choice.
"Hunger striking is the sole peaceful means that I have to protest my indefinite detention.
“I have not decided to do this lightly. Each day of the strike is an ordeal. The process of being force-fed hurts a great deal, particularly because I had a prior surgery in my nose so my nerves there are very sensitive. It is both painful and risky for me to be force fed."
Hadjarab, also being force-fed, said: “I do not want to die, but I am prepared to. All I am asking is that I be given the choice whether to eat.”
Cori Crider, Reprieve’s Strategic Director and counsel for the men, told HuffPost UK: “After nearly a dozen years of limbo, the last thing my clients feel they have left is the basic dignity of choosing what goes into their bodies.
"For the US military to strip this final right from them is appalling – which is why everyone from the head of the American Medical Association to President Obama has condemned force-feeding.
"Nabil and the other prisoners need Obama to wake up to the crisis in Guantánamo, which is the worst he will face of his presidency. History will closely study how these men were treated.”
Around 120 detainees at Guantanamo are on hunger strike, out of 166 in total. The US has claimed that force-feeding is currently being used on 44 of those men.
Jon B Eisenberg, an lawyer from Oakland, California who is working with Reprieve on the lawsuit, said: “Force-feeding of prisoners is inhumane and a violation of medical ethics. When it is done for the purpose of keeping Guantanamo detainees alive so that they may continue to be held indefinitely without a trial of any sort, it is nothing short of grotesque.
"President Obama has himself condemned the force-feeding, but he has not seen fit to stop it. His deeds have not matched his soaring rhetoric.”
Cameron recently wrote to Aamer's teenage daughter Johina, promising that the UK government is working to secure her father's release. Aamer has been cleared for transfer out of the detention camp, but not for release.
The Guantanamo detainee, who is a Saudi citizen, was accused of leading a fighting unit for Al Qaeda in Afghanistan in 2001.
Aamer, who is also suspected of communication with shoe bomber Richard Reid, has a British wife and four children who all live in South London. He has been detained for 11 years.
His defence claims all evidence against Aamer came from unreliable witnesses or was gained under torture.
Amnesty International UK Director Kate Allen said her charity had stepped up its lobbying of the Prime Minister with regards to Aamer: “David Cameron’s recent remarks about Shaker’s case are encouraging but we need to see the UK and the USA urgently agreeing to his release and return to the UK.
“We need follow-through after the Prime Minister’s letter and sustained diplomatic activity.
“Time is of the essence - I can’t stress this enough. There’s an understandable concern that detainees at Guantánamo - Shaker included - could die at the camp before they are ever released.
“Does Mr Cameron want to be remembered as the prime minister who acted too late to save Shaker Aamer?”