[Uttephabeta]

BANGKOK - The founder of Thailand's royalist "Yellow Shirt" protest movement on Tuesday denied charges of insulting the monarchy, saying his trial was politically motivated.

Sondhi Limthongkul, one of Thailand's most controversial political figures, faces up to 15 years in prison if found guilty over excerpts of a speech by a rival political activist that he repeated in 2008.

"My aim was to tell people that there was an insult against the monarchy, and to encourage the police to take legal action against those who said it," Sondhi told Bangkok's Criminal Court.

"I don't have any intention to insult the monarchy and all my past actions show my loyalty to the monarchy," the media mogul added, blaming unspecified political opponents for pushing the case against him.

Protests by the Yellow Shirts helped to trigger a coup by royalist generals in 2006 that ousted former premier Thaksin Shinawatra, Sondhi's longtime rival.

Thaksin now lives in self-imposed exile overseas to avoid a jail term imposed in his absence for corruption, but his younger sister Yingluck Shinawatra is the current prime minister.

In 2010 Sondhi was convicted of defaming Thaksin and handed a six-month suspended jail sentence.

The royal family is a highly sensitive topic in politically turbulent Thailand. King Bhumibol Adulyadej, who is revered as a demi-god by many Thais, has been hospitalised since September 2009.

The woman whom Sondhi quoted, Daranee Charnchoengsilapakul - a hardcore supporter of the rival "Red Shirts" - was jailed for 15 years in December for her comments, which she made during political rallies four years ago.

Thailand has seen a series of rival street protests in recent years by the Yellows and the mainly poor and working-class Red Shirts, whose demonstrations in Bangkok in 2010 sparked a military crackdown that left about 90 people dead.

In February, the Criminal Court sentenced Sondhi to 20 years in prison for corporate fraud in a case dating back to the mid-1990s. He was released on bail pending an appeal hearing on those charges.

The Yellows claim allegiance to the throne and are backed by the Bangkok-based elite, although their influence has waned since 2008 when they seized Bangkok's airports and stranded hundreds of thousands of tourists.