"Tuesday [May 27] will determine our victory. If millions of people do not show up on that day, I will turn myself in. I will give up whether we win or lose. We have done the best we can and we will accept the outcome," said Suthep.
"Until then, we will dedicate ourselves to this mission and it will end on May 27. We have been down this road long enough. This movie has been showing for a long time."
"It's a pity the announcement of the senators on Friday could not give a specific time frame [for naming a premier]," Suthep was quoted as saying by the Bangkok Post.
"Unlike them, the people have been in this fight for a long time and they deserve to know when they will succeed."
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He said the "last mission" will start tomorrow and end on May 26.
Yingluck was forced to step down after the country's Constitutional Court on May 7 found her and her nine minister guilty of abuse of power.
Suthep said he would meet representatives of state enterprise unions, retired civil servants tomorrow to draw up plans for the protest during the week.
He said PDRC supporters would visit caretaker cabinet ministers and demand their resignation and added that civil servants would be asked to challenge the authority of ministers by refusing to take their orders.
The anti-government protesters accuse Yingluck of acting as a proxy for her fugitive brother, former premier Thaksin Shinawatra, who was ousted in a coup in 2006.
Thaksin lives in Dubai on a self-exile to avoid jail for a corruption conviction that he says was politically motivated.