Suriyasai Katasila, spokesman of the People's Alliance for Democracy, said there were indications that the country was facing a crisis.

"Thailand is on the brink of suffering a great loss," Suriyasai said.

Thaksin will have to sacrifice his power and leave politics unconditionally to end the crisis, Suriyasai added.

The PAD campaigner said the first sign of doom was the alleged collaboration among the Thai Rak Thai Party, the Election Commission and caretaker Senate Speaker Suchon Chaleekrua to challenge the power of the three highest courts.

He said the Supreme, Administrative and Constitution courts wanted the EC to be replaced before another election, but Thai Rak Thai, the EC itself and Suchon were using any means to help the commissioners cling to their jobs.

If the courts' power is challenged and they lose credibility, society could descend into lawlessness and the Thai Rak Thai would take absolute power, Suriyasai said.

He called the so-called "Finland Plot", which allegedly intends to undermine the monarchy, the second sign of doom.

Several academics claimed Thai Rak Thai planned the plot to gain power, he said, adding that the party had failed to answer allegations about the plot and simply used lawsuits to silence its critics.

Suriyasai said the third sign of an impending crisis was the confrontation between Thaksin's supporters and opponents, which could result in civil war.

"I call on Thaksin to examine his conscience and realise that it's time to make the greatest sacrifice of his life," Suriyasai said.

He said Thaksin had gained more profit from the country than anyone else so he should repay the Kingdom.