BANGKOK - Thailand's Red Shirt leader Jatuporn Prompan was sentenced by the Supreme Court to one year in prison here on Thursday on defamatory charges against former prime minister Abhisit Vejjajiva.

The Supreme Court ruled Jatuporn, leader of the United Front for Democracy against Dictatorship, better known as the Red Shirt movement, guilty as charged and sentenced him to one year in jail, following a libel lawsuit filed by Abhisit against him several years ago.

Abhisit sued that Jatuporn had publicly accused him of having ordered fatal crackdowns on Red Shirt demonstrators during a street protest against his government in 2009 and of stalling the submission of a petition seeking a royal pardon for ousted prime minister Thaksin Shinawatra.

Jatuporn made the allegations on Oct 11 and Oct 17 2009 when Abhisit served as prime minister.

The Red Shirt leader has been detained in prison since this July as he was sentenced to one year in prison by the Supreme Court in another defamatory lawsuit brought forward by Abhisit.