Nicolaides, 41, was initially sentenced to six years' jail last September for the crime of lese-majeste criticising the Thai royal family the jail term later being halved due to his guilty plea. But a royal pardon from Thailand's King Bhumibol Adulyadej on Friday led to his immediate overnight deportation.

Arriving at Melbourne Airport yesterday at about 1.30pm, he hugged his partner, Jintana Suttanu, his father Socrates, brother Forde, and other family members.

''I am angry, I am frustrated, I am perplexed,'' Nicolaides said of his harrowing ordeal.

The emotional trauma of his experience was compounded by the news his mother had suffered a stroke during his incarceration.

''I learned only a few minutes before boarding my flight that my mother had suffered a stroke,'' Nicolaides said.

''A few hours before then, I was informed I had a royal pardon and asked to kneel before a portrait of the king, a royal audience of sorts, and be informed that I had been pardoned.

''A few hours before that I was climbing out of a sewerage tank that I fell into in the prison.''

He had written a book entitled Verisimilitude, a fictional account of life in Thailand. Part of the book, which sold only seven copies, dealt with the sex life of an unnamed crown prince, and it was those 12 lines that caused his arrest and conviction.

His lawyer Mark Dean, SC, said Nicolaides was made an example of by the former Thai government which was determined to appear tough on critics of the country's monarchy.

''I think it's fair to say that Harry was a political prisoner, and that the reason for the commencement of this case against him were inextricably linked to the political crisis in Thailand in August 2008,'' he said.