The 41-year-old Australian was arrested under the Thai law of lese majeste, the offence of insulting the monarchy. He was thrown in a crowded, stinking prison cell, where - despite repeated attempts to get bail - he remains.

The charge was apparently prompted by a 103-word passage on the private affairs of an unspecified Thai crown prince. It would never have been noticed had it applied to British royals, but offending the Thai royal family is no laughing matter. The English teacher and part-time writer faces up to 15 years in prison.

His devastated family fear for him in a squalid cell he shares with more than 50 inmates. 'He is really suffering,' says older brother Forde Nicolaides, who lives in Melbourne. 'His mental and physical condition must be pretty atrocious by now. We fear the worst for him. The legal process has not worked at all.'

In one letter to his elderly parents Nicolaides recounts how he watched one prisoner die after guards ignored pleas for medical assistance. 'Last week I saw a dead man placed on a wooden cart and carried out of the compound,' he wrote.

'This week I saw violent fights between inmates in my cell - a regular occurrence. The air is always thick with the smell of rotting food and open sewage.'

Nicolaides' Australian lawyer, Mark Dean, says 32 lese majeste cases are currently being pursued by Thai authorities, an unusually high number. These include Thailand's highest-profile social critic, Sulak Sivaraksa, who was arrested over a speech made almost a year ago in which he criticised lavish government spending on King's Bhumibol Adulyadej's Golden Jubilee celebrations.

Two activists have also been charged because they failed to stand up when the national anthem was played before cinema screenings.

'There is no doubt that this charge is being used by the current Thai government to show the population that it supports and has the support of the monarchy,' Mr Dean says. 'These cases have commenced at a time of great political instability.'

The lese majeste charges against Nicolaides are believed to have been prompted by his novel.

After finishing Verisimilitude in 2005, he sent copies to the Royal Palace and Ministry of Culture to establish whether there was any problem with the content. There was no reply, and a copy was accepted by the National Library of Thailand. Authorities are understood to have received a complaint about the contentious three paragraphs in 2006, and in March this year an arrest warrant was issued.

Nicolaides, who was unaware of the charges against him, then travelled to and from Thailand five times before he was finally picked up at Bangkok's Suvarnabhumi airport on August 31.

Forde Nicolaides had arranged to pick his brother up at Melbourne Airport the next morning. 'I haven't seen him since 2003 - he's been travelling a lot - so I was looking forward to it,' he says.

The offending words are understood to relate to a crown prince, although it is unclear if they relate to a fictional royal or the real Crown Prince Vajiralongkorn.

'I've read some of the book but not all of it,' says Forde Nicolaides. 'It seems to be a fictional piece based on contemporary Thailand through Harry's eyes. There are different themes running through it but it is in no way about the monarchy. It's not in any way critical of the monarchy.'

In an interview with a British newspaper in September, Nicolaides offered to apologise for his 'reckless choice of words'.

'I've been getting icy stares from men covered in tattoos,' he wrote of fellow inmates who were hostile because of the charge against him. 'On the first night I would have committed suicide if I'd had the means.'

Nine days ago prosecutors finally laid charges in Bangkok Criminal Court. During a brief appearance, a visibly distressed Nicolaides pleaded not guilty.

He was again remanded and must wait until January 19 for his next day in court.

Legal observers believe the Australian's best hope is for a pardon from the king. The 81-year-old is the world's longest serving monarch, having been on the throne for 62 years.

Two years ago he intervened in the case of a Swiss man, Oliver Jufer, who went on a drunken spree in the northern city of Chiang Mai and defaced images of the king. Like Nicolaides, Jufer was held for four months before being tried and sentenced to 10 years in prison.

Weeks later he was pardoned and deported to Switzerland. The Nicolaides family say they cannot afford to pin their hopes on a similar outcome.

And Mr Dean argues his client is effectively being held as a political prisoner because the authorities only acted after the political situation in Thailand worsened.

On that basis, he says, the Australian government should be putting maximum pressure on the Thai authorities to allow Nicolaides to return home.

He notes that all Thais charged with lese majeste get bail, whereas Nicolaides' repeated bail attempts have been rejected.

'It is our view that the minister should put Nicolaides before the sensitivities of the relationship between the two countries,' says Mr Dean.

While Australian embassy officials in Bangkok have regularly visited Nicolaides in jail, the department of foreign affairs in Canberra says it cannot intervene in another country's judicial process.

Forde Nicolaides believes they should be doing far more. He fears for the health of his brother and of his elderly parents. 'They are deteriorating each day because they feel, and this applies especially to my father, who is 83, that they are not going to see their son again.'

Reporters Without Borders has also called for Nicolaides' release. 'Keeping him in custody is an abuse that just highlights how the government is using the king's political popularity to win over Thais,' it said. 'Nicolaides must not be used as a scapegoat or handy bogeyman.'