The government has done very little for the red-shirts, people who sacrificed their lives helping it come to power, and instead focuses on using money to promote the popularity of the Pheu Thai Party, Jatuporn Prompan said on Wednesday.
Mr Jatuporn, a key member of the United Front for Democracy against Dictatorship (UDD), implied that the red-shirts might withdraw support for the government if their contribution is not rewarded.
It was the first time he had spoken out since he was omitted from latest cabinet reshuffle, despite speculation he was long overdue a seat.
He said he was "still happy and all smiles".
"Many people asked me why I can still smile not being named to the cabinet. Some people said I can still smile because I have been paid an amount of money in return for not getting a cabinet post.
"I want to tell everyone that I will never sell my soul. I will never sell the honour of being a red-shirt," he said at a press conference.
Mtr Jauporn said more than 100 people died, 2,000 were injured, and many others put in jail.
"These figures guarantee my heroic deeds which are far more honorable than a cabinet post," he said.
"After I was not named to the cabinet, Thida Tawornseth asked me to take over from her the UDD chairmanship. I thanked her and told her to continue doing her duty because my health is not good."
Mr Jatuporn said has chronic back pains.
He said he told Ms Thida to continue to safeguard democracy and a democratic government.
"But a democratic government must answer to the people's needs," he added.
He said two years after helping the Yingluck Shinawatra government into power, the red-shirts had received nothing in return for the loss of so many lives.
The government had not dared to bring a charter amendment bill to a third-reading. It did not dare ratify the power of the International Criminal Court (ICC). It had not seriously pushed forward the many bills seeking amnesty for people on all sides of the political conflict, he said.
Mr Jatuporn said he had a feeling that the government's priority was the 2.2 trillion baht infrasture loan bill and the annual budget, and charter amendment bills, before taking up amnesty bills for consideration.
He said he did not want the government to care more about money than about the people.
"I would like to ask the Pheu Thai Party to care for the people, not only for some 20 people who have been put in jail, but for more than 10 million red-shirts whose 20 million eyes are on the government.
"I want the government to show them sympathy, because if it happens to be toppled again they can again rise to fight for it.
"The red-shirts are not a sure thing the Pheu Thai Party can do anything with. We are friends. According to Ms Thida's two-legged theory, Pheu Thai and the UDD must walk together.
"But, I am not sure if today Pheu Thai still regards the UDD as one of the two legs. They may think they can walk with just one leg," Mr Jatuporn said.
Mr Jatuporn said he wanted the government to answer the UUD's three demands in return for continued support from the red-shirts: not to be corrupt, not to indulge in power, and not to betray the people.
"If you are honest and sincere, we would be ready to die for you for another time. If you are not honest and forget that your path to power is soaked with blood and tears and allow corruption to prevail, the government will collapse," he added.
Mr Jatuporn repeated that the government should help the people first, before money.
Former prime minister Thaksin Shinawatra had promised a cabinet seat for Mr Jatuporn but his name has never ppeared on the list of Prime Minister Yingluck Shinawatra, despite reshuffling her cabinet four times.
Only Deputy Commerce Minister Nattawut Saikuar, a key red-shirt leader, represents the UDD in the cabinet.
Mrs Thida was full of praise for Mr Jatuporn, saying that he is always a great hero in the hearts of the red-shirts, if not in Government House.
She accused the white-masks of trying to exacerbate he political situation. But the real threat to the government were the indepdent organisations and the old clique working hand in hand to bring an end to the Pheu Thai-led administration, she said.
The UDD was prepared for a possibly intensified situation, she said. The movement had improved communications with its members across the country, she added.