Ending 40-year-old relationship with the Bharatiya Janata Party (BJP), former Karnataka Chief Minister BS Yeddyurappa on Friday formally quit the party.
Yeddyurappa said he has sent his resignation from the BJP to party president Nitin Gadkari.
He also resigned from the Karnataka Assembly.
The 70-year-old leader submitted his resignation to Speaker KG Bopaiah at the state secretariat and reportedly asked him to accept it immediately.
Yeddyurappa was in tears on Friday morning ahead of his resignation from the BJP.
Speaking at a public meeting at Freedom Park in Bangalore, Yeddyurappa said: "I have resigned from primary membership of BJP and sent letter to party president Nitin Gadkari."
Speaking to reporters, Yeddyurappa criticised the BJP leaders in Karnataka and said some of them had stabbed him in the back.
"Some of our state leaders stabbed me in the back. So many things have happened, I tolerated everything for one year. Finally I took the decision to float a new party," Yeddyurappa said.
"Despite all my contributions to the party, and getting so many Lok Sabha seats, still BJP has not treated me well," he said.
He said he was leaving BJP ´because of our own (BJP) people´.
"They don´t want me to continue in the party. That is why I am resigning from the primary membership as also MLAship," he said.
"Some people did not want me to continue as the Chief Minister. They tried to put me in the dock. I tolerated in the past one year with a lot of patience," Yeddyurappa said.
He said he was leaving the party with ´deep sadness´.
Meanwhile, the entire BJP unit in Yeddyurappa´s constituency has quit on Friday.
Reacting to it, Yeddyurappa said: "I have not requested anyone to resign from the BJP for the time being."
"I am also requesting my supporting MLAs not to resign from their membership for now," he said.
Yeddyurappa has announced that he would launch his own political party, Karnataka Janata Party (KJP) on December 9.
The leader has said he would not destabilise the Karnataka government. "We are not going to destabilise the Karnataka government. I made him (Jagadish Shettar) the chief minister. I don´t want the public to blame me," he told NDTV earlier this week.
On July 31 last year, Yeddyurappa was forced to resign as chief minister of Karnataka after he was indicted by the then Karnataka Lokayukta N. Santosh Hedge in the illegal mining report.
He and his family members were named by Hegde in what was called a Rs 16,000 crore illegal mining scam.
Yeddyurappa walked out of jail on November 8 on bail.
The 70-year-old leader is credited to bringing the BJP to power in Karnataka.