Bangkok  - Bangkok Criminal Court Friday sentenced a Thai woman to 18 years in jail for committing lese majeste by insulting members of the royal family in public speeches made at political rallies last year.

The court found Daranee Cherngcharnsilpakul, nicknamed Da Torpedo for her fiery oratory style, guilty of three charges of lese majeste, carrying sentences of six years each.

Daranee said she will appeal the verdict.

"I will appeal the verdict up to the Supreme Court to find out if there is any justice in this country," she said after hearing her sentence.

"This country is closing its eyes and ears," Daranee told reporters.

The court found Daranee guilty of insulting Thai King Bhumibol Adulyadej, Queen Sirikit and the institution of the monarchy in speeches she made at the Royal Grounds in Bangkok in June and July last year in front of thousands of supporters of ousted premier Thaksin Shinawatra.

Under Thailand's tough lese majeste law, anyone found guilty of insulting a member of the royal family or the monarchy may face up to 15 years in jail.

There has been a rash of lese majeste cases over the past two years as various protest groups have claimed support or opposition from the monarchy, which is expected to remain above politics under Thailand's constitutional monarchy.

In April, Bangkok Criminal Court found Suwicha Thakho, an oil engineer, guilty of posting a picture deemed insulting to the Thai monarch on a website, for which he was sentenced to 10 years in jail.

In January, the same court found Australian national Harry Nicolaides, 41, guilty of lese majeste for 12 lines he wrote in his 2005 novel, Verisimilitude, which referred to an unspecified crown prince's love life.

Nicolaides was released under a royal amnesty a month later.

Prime Minister Abhisit Vejjajiva has promised to review the use of lese majeste laws, but so far, authorities seem as keen as ever to clamp down on any hard discussion of the role of the monarchy in politics and society.

Although Abhisit has backed the legislation as a stabilizing force, he said his government would "uphold the law, but we must not allow people to interpret the law too liberally and abuse the law."

In a speech delivered two years ago, the king obliquely criticized the lese majeste law himself, noting that he should not be above criticism.