Thailand’s Supreme Court on Thursday upheld the appeal court’s decision requiring Jatuporn Prompan to continue to serve his prison sentence for another 11 months and 16 days, in the defamation lawsuit brought against him by former prime minister Abhisit Vejjajiva in 2009.

Jatuporn was faced with two different lawsuits, related to two speeches he gave during political demonstrations in 2009 and 2012. The courts found Jatuporn guilty of defamation of Mr. Abhisit in both cases and sentenced him to 12 months in prison on each conviction.

Jatuporn served the time for one of the cases and, in 2018, the first court mistakenly ordered that he was not required to serve time for the second.

Abhisit, however, appealed, which the Court of Appeals granted, ordering Jatuporn to complete the punishment. Jatuporn had been released on bail until Thursday, when the Supreme Court upheld the appeals court ruling.

Having already served 14 days in jail for the second conviction, Jatuporn will have to serve another 11 months and 16 days to complete the term. He was taken to Bangkok Remand Prison after the ruling.

Jatuporn, a veteran political activist, said he has been in and out of prison four times and knows exactly what to do. He has prepared by getting the COVID-19 vaccination, as well as dental care, he said.

He had, to date, been leading an anti-government movement called “Thai Mai Thon” (Impatient Thais) which, Jatuporn said, will go on, even without him.

The movement will join forces with other anti-government groups, such as that led by Sombat Boonngamanong, which will hold a demonstration this Saturday.