The three remaining election commissioners, now widely considered the biggest obstacle to staging a trustworthy general election, have come under renewed pressure to resign after a royal decree was handed down setting October 15 for national poll, political observers said yesterday.

The pressure could escalate drastically tomorrow, when the court is set to rule on criminal charges related to the commissioners' controversial handling of the April 2 general election, which was later nullified by the Constitution Court.

Already, calls for the commissioners to quit, from opposition politicians, senators and academics and in newspaper articles, are reaching a deafening pitch.

They have asked the commissioners to consider the King's message accompanying the royal election decree, in which His Majesty stated that it was his wish to see a "free and fair" election.

Insisting that a credible election is impossible with the three commissioners still in charge, a group of senators is contemplating asking the Constitution Court to remove them on grounds that they lack constitutional qualifications.

The first attempt by the 35 "minority" senators to purge the Election Commission of the three incumbent commissioners was unsuccessful because of the senators' "caretaker" status.

But the senators have been revitalised by the King's unprecedented public wish to see a clean and reliable election that could put Thailand firmly back on a democratic path.

"We hope the Constitution Court [which rejected the senators' first petition] will reconsider its ruling on the scope of the caretaker senators' authority and responsibility, simply because by doing so the Constitution Court will help ensure a clean and fair election," caretaker Bangkok senator Sak Korsaengruang said yesterday. "That is the wish of His Majesty."

The Constitution Court's ruling against the commissioners is needed as a "Plan B" by those who do not trust them to oversee the next election.

Even if the three are found guilty by the Criminal Court tomorrow, there will be legal debate on whether they would automatically lose their positions, given their right to appeal to higher courts.

But the royal decree has thrown the ball back into caretaker Prime Minister Thaksin Shinawatra's court, and a "guilty" verdict could force him to make a public stand on the highly controversial and widely mistrusted commissioners.

Having complained, domestically and internationally, that Thailand's democratic course had been blocked by influential, undemocratic forces, all eyes would be on him if the only thing standing between a return to democracy and lingering political turmoil was the current election commissioners, accused by many of being pro-Thai Rak Thai.

The People's Network for Elections in Thailand, an independent poll-monitoring agency, has voiced serious doubts about the October 15 election having any credibility if the three commissioners were to oversee it.

The most recent Dusit Poll, conducted after the royal decree was announced, showed that the majority of respondents, mostly residents of Bangkok and its suburbs, wanted the commissioners to step down.

The Democrat-led opposition bloc, which boycotted the April 2 election, has challenged Thaksin to "do away with" the three commissioners.

"What is Thai Rak Thai so afraid of if the next election is overseen by a new Election Commission?" asked Democrat leader Abhisit Vejjajiva. "He's been going on and on about national reconciliation. Now it's time he proves it."

Suriyasai Katasila, key member of the anti-Thaksin People's Alliance for Democracy, and Mahachon Party leader Sanan Kachornprasart also piled pressure on the caretaker prime minister, saying His Majesty's wish would not be granted if the three commissioners remained in charge.

"Everyone sees the current EC has lost its legitimacy," said Suriyasai. "What worries me is that the commissioners and Thaksin have pretended not to see what the rest of the country sees. If they insist on allowing the commissioners to organise the next election, who will take responsibility for a new crisis?"