Bangkok - Anti-government protestors marched through central Bangkok Monday on the eve of a verdict in a key corruption trial against their prime target, former prime minister Thaksin Shinawatra.

The marchers with the People's Alliance for Democracy (PAD) listened to speakers accuse the current prime minister, Somchai Wongsawat, Thaksin's brother-in-law, of being a Thaksin puppet and demand that he stand down. They also poured scorn on Somchai's promise of a fair investigation into police violence during a protest this month.

The Supreme Court's criminal division for political office holders, a panel established by the constitution to curb political corruption, was scheduled to deliver its verdict on charges that Thaksin's wife, Pojaman, bought a suspiciously cheap premium plot of land in central Bangkok at a 2003 government land auction.

It could be the first time Thaksin, who is living in self-imposed exile in London, has been found guilty of a crime - abusing his office - after multiple corruption investigations were fired at him after his ouster in a bloodless, September 2006 military coup following five years in office.

A smaller demonstration by a pro-government group, the National United Front of Democracy Against Dictatorship, also formed outside the National Police headquarters Monday to demand that all police help prevent another military coup, the Thai News Agency said.

Bangkok has been roiled by political tension because Thaksin, and by extension his subsequent proxy governments, remain attractive to the rural poor, who admire his populist economic policies and vote for his political supporters.

However, Thaksin's urban critics, including powerful elements in the army and people close to the palace, accused him of mass corruption, dividing the nation, and undermining democracy and the monarchy.

Both sides have well-organized mobs and have threatened to gather at the Supreme Court Tuesday for the verdict. They have clashed before under intransigent leaders, many of them former military men.

A former deputy police chief with a reputation for harshness, Salang Bunnag, has organized a merit-making ceremony at the Royal Plaza on Wednesday, which he claims would include many retired and serving officers. Salang has claimed to be poised to oust PAD protestors who have been occupying Government House, the seat of the executive branch of the government, for weeks.

A PAD coordinator told the Nation newspaper that anti-government protestors would like the military to overthrow this "corrupt" government.

"I don't want to see another coup but will accept it if it leads to political change by the people," Suriyasai Katasila said.

The PAD has proposed abandoning one-man-one-vote principles in favour of a mixture of elected and appointed parliamentarians, although its proposals are vague.

Its marchers handed out CDs Monday that purportedly showed excessive police violence against PAD demonstrators, who unsuccessfully tried to prevent the opening of Parliament a fortnight ago. Two people died and more than 400 were injured in the clash. (dpa)