South Ribble Council has been left with no party having overall control, following the resignation of four Tory councillors from the group.
Coun Paul Wharton had been due to appear before a disciplinary meeting of the group at South Ribble Civic centre on Saturday. He had previously led a vote of no confidence in council leader, Margaret Smith.
However, he and three fellow Conservative councillors resigned from the group before the meeting.
Coun Wharton, Couns Barbara Nathan and Michael Nathan and Coun Andrea Ball will now sit as Independent Conservatives.
Coun Wharton said they had been left with no other option but to quit the group and has now called for the leader to resign.
He said: “The meeting didn’t happen because we resigned prior to the meeting.
“We resigned due to significant failures in the leadership. We can’t support (Margaret Smith) any longer.
“This leaves the council in no overall control.
“A lot of work needs to be done to rebuild the reputation of the council. It is in tatters.
“Margaret Smith has to resign.”
Coun Wharton had previously criticised the leader for not releasing the interim report into a taxi investigation, launched after reports of child sexual exploitation of two girls by taxi drivers.
The secret report was leaked to the press in April, months after being sent to the council.
The council was criticised in it for failing to carry out proper background checks on drivers, and since then a new probe has been launched into how a cabbie who tied up a disabled boy had his licence renewed.
Coun Ball said she had resigned the whip after feeling “bullied” by some party members.
She said: “My main concern is my constituents. I felt I was being stopped from doing my job. We want South Ribble to be back where it should be. We need to try to unite everybody.”
The Evening Post has so far not been able to reach Coun Smith for comment on the councillors’ resignations. The Conservative party’s North West regional office has also been contacted for comment.
Coun Paul Foster, leader of the Labour group at South Ribble Council, said: “I respect the decision by the four councillors to resign from the Conservative group after the serious failings caused by the poor leadership which has caused turmoil in the Council.
“The Labour group is determined to work in the best interest of South Ribble residents to have an all inclusive solution for the benefit of the borough. We are exploring options of a collaboration of all councillors from all parties and with strong leadership to provide a vision for the future.
“This council is facing some huge challenges, one of which is a £3m budget deficit in the next two years, an issue the executive has collectively failed to deal with.”