Former Tory Party chairman Grant Shapps has said there is growing support among MPs for a leadership contest following Theresa May's chaotic conference speech.
Mr Shapps, who has been revealed as one of the ringleaders of the plot to oust the Prime Minister, said there is a "broad spread" of opinion among Conservative MPs who believe they cannot carry on as they were.
"They are Remainers, they are Brexiteers," he told BBC Radio 4's Today programme.
"A growing number of number of my colleagues, we realise that the solution isn't to bury our heads in the sand and just hope things will get better.
"It never worked out for Brown or Major and I don't think it is going to work out here either."
Senior ministers continued to rally around Mrs May, with Environment Secretary Michael Gove - who ran against her in last year's leadership election - insisting there was no need for a contest.
"The Prime Minister has been doing a fantastic job," he told the Today programme.
"She showed an amazing degree of resilience and courage this week, of a piece with the fantastic leadership she has shown through the time that she has been Prime Minister."
It is thought that around 30 Tory MPs are backing the calls for a leadership election - short of the 48 needed to force a contest under party rules.
Mr Shapps would not be drawn on the number but did confirm that he had the support of five former Cabinet ministers.
Mr Shapps said that while ministers were publicly backing the Prime Minister, in private some believed she should go.
He said the plan had been to approach Mrs May privately but the Government whips had leaked details to the Times.
"I am slightly surprised that the whips decided to brief a newspaper about it. That was their idea to smoke people out," he said.
"The intention was to be able to go to Mrs May with a list of names - probably with the former Cabinet ministers going to see her."
He added: "It will have to be her decision. I had rather hoped that we would be able to get to point where we could go to her privately and have this conversation; I am very sorry that the whips have not made this possible."
Charles Walker, vice chairman of the powerful Tory backbench 1922 Committee, said it was clear that the rebels lacked the support to force out the Prime Minister.
"Number 10 must be delighted to learn that it is Grant Shapps leading this alleged coup," he told the BBC.
"Grant has many talents but the one thing he doesn't have is a following in the party. I really think this is now just going to fizzle out.
"What you are seeing here is probably a coalition of disappointed people who think their brilliant talents have not been fully recognised."
Mr Gove said the "overwhelming majority" of Tory MPs - including the "entirety" of the Cabinet - want Mrs May to carry on.
"The truth is that the overwhelming majority of people want the Prime Minister to concentrate on doing the job which 14 million people elected her to do earlier this year," he said.
"I think it would be disrespectful to those 14 million people to do anything other than concentrate on those areas where action is necessary."