Locked up for breaking Thailand's most enduring taboo, the kingdom's "royal insult" prisoners say they face mistreatment from jail guards and are shunned even by common criminals.
They are viewed by supporters as prisoners of conscience, and in most countries would never have been locked up.
But in Thailand they carry the stigma of flouting one of the nation's most controversial laws: defaming the monarchy.
"Some of the wardens took me to a different part of the jail and ordered other prisoners to beat me," said Thantawut Thaweewarodomkul, who is serving a 13-year term for posting online content deemed offensive to the royals. The incident, which happened soon after he was incarcerated three years ago, left him with two black eyes, the 40-year-old said at the high-security Bangkok Remand Prison.
The former administrator of the Nor Por Chor USA website, linked to the red-shirt protest movement loyal to ousted prime minister Thaksin Shinawatra, he was convicted under controversial lèse-majesté and computer-crime laws.
He is one of nine lèse-majesté prisoners in the kingdom, according to the Office of the Human Rights Commission of Thailand, which says there have been 241 cases under the law since 2007, with an unknown proportion still under investigation.
Benjamin Zawacki, Southeast Asia researcher for Amnesty International, said lèse-majesté is seen as an "offence to society" and not just the four individuals it is designed to protect - the Thai king, queen, heir or regent.
The royal family is an extremely sensitive subject in politically turbulent Thailand. King Bhumibol Adulyadej, 84, is revered, but he has been in hospital since September 2009.
Rights campaigners say the law has been politicised, with many of those charged linked to the red shirts, whose street protests in Bangkok in 2010 triggered the worst civil unrest in decades with about 90 dead.
Thaksin's sister Yingluck Shinawatra leads a government elected last year, but lèse-majesté cases have continued and she has dismayed activists by ignoring calls for reform of the law.
Prisoners say, however, that their conditions have improved under the new administration.
In May Ah Kong, a 62-year-old grandfather, died in custody while serving a 20-year sentence for sending text messages to an aide of former prime minister Abhisit Vejjajiva that were deemed insulting to the royal family.
An autopsy showed the inmate - known in Thailand as "Uncle SMS" - had been suffering from liver cancer.
But the death of one of the country's best known lèse-majesté prisoners generated a rare outcry among ordinary Thais.
Amnesty views people incarcerated solely for lèse-majesté - which carries a maximum penalty of 15 years in jail on each count - as prisoners of conscience.
"If that is the only law under which they have been in prison they should be released. Treatment in prison, that's a conversation we shouldn't even be having," said Zawacki.