Human Rights lawyer Arnon Nampa, 39, has been serving a four-year sentence since last September after a criminal court found him guilty over remarks about the monarchy at a speech during a 2020 rally. The sentences will run consecutively, so he will serve eight years, local media said.
Thailand's lese-majeste law protects the palace from criticism and carries a maximum jail sentence of up to 15 years for each perceived royal insult, a punishment widely condemned by international human rights groups as extreme.
Wednesday's verdict is the second of 14 cases against Arnon, a lawyer-turned-protest leader of a youth-led democracy movement that held protests in Bangkok in 2020, calling for reform of the monarchy.
"Arnon has denied wrongdoing," his lawyer Kritsadang Nutcharat told Reuters, adding that his team would lodge an appeal and if necessary, take the case to the Supreme Court.
Arnon has chosen not to request bail for his cases and stayed in jail after the court rejected a previous request on the grounds that he would escape.
The verdict against Arnon is a setback for groups seeking to amend the lese-majeste law, a key policy proposal from Thailand's progressive Move Forward Party that won an election last May but was blocked from forming a government by lawmakers backed or appointed by the ultra-royalist military.
At least 262 people have been charged with lese-majeste offences since 2020 according to legal aid group, Thai Lawyers for Human Rights.
Most of those cases are related to the youth-led democracy movement, which has since lost momentum having once posed one of the biggest challenges to Thailand's royalist, conservative establishment.
