A 37-year-old man was sentenced to more than three years in prison on Thursday for selling copies of a controversial Australian documentary about Thailand's royal family, his lawyer said.
The imprisonment of Ekachai Hongkangwan is the latest in a series of tough sentences handed down by the kingdom's courts for royal defamation, to the dismay of human rights campaigners.
"The court found him guilty of lese majeste and sentenced him to five years, but due to his useful testimony the sentence was reduced to three years and four months," lawyer Anon Numpa said after the sentencing on Thursday.
He said he would take the ruling to the Constitution Court.
Mr Anon argued that Article 112 of the Criminal Code, the lese majeste law, violated the constitution as it sought to impose excessive punishment on offenders and ran counter to the freedom of expression guaranteed by the charter.
Ekachai Hongkangwan (AP Photo by Apichart Weerawong)
Ekachai, a supporter of the red-shirt United Front for Democracy against Dictatorship, was also fined 66,666 baht (about US$2,270) for selling CDs without a licence.
He was arrested in March 2011 on charges of possessing 10 WikiLeaks documents and about 100 CDs, which contained a segment of an Australian Broadcasting Corporation (ABC) programme, "Foreign Correspondent", dating from 2010 about the Thai royal family.
Pol Sen Sgt Maj Nakorn Kongklin, of Chana Songkhram police, told the court he posed as a buyer and arrested Ekachai after the defendant handed him one of the CDs.
He said a search of Ekachai's body and immediate possessions yielded 70 copies of the CD. Police later seized printouts, WikiLeaks documents and several more CDs.
Thailand warned at the time that the Australian programme was broadcast that it could affect ties with Canberra.
Rights groups have criticised the kingdom's royal insult laws as an attack on freedom of expression.
Under the legislation, anyone convicted of insulting the King, Queen, heir or regent faces up to 15 years in prison on each count.
In January the European Union said it was "deeply concerned" by an 11-year jail sentence handed to a former magazine editor in connection with the publication of two articles containing comments deemed to constitute lese majeste.