Amber Rudd urges the Prime Minister not to resign at crucial 'turning point' for Britain

They believe that if they can recruit another 15-20 MPs they will have enough support to approach Mrs May and tell her to go, and believe there is a “50-50” chance of doing so before Monday.

The pound yesterday dropped to its lowest value in a month as speculation over Mrs May’s future continued. Mrs May was said to have spent the day at home and has no major public appearances planned until Parliament returns next week.

In today's article, Ms Rudd takes the trouble to namecheck David Davis, Boris Johnson and Philip Hammond and insists they are determined to help realise Mrs May’s vision for Britain. The Cabinet has been at odds over the Government's Brexit strategy but the Home Secretary sets out how they can work together.

She writes: “We, Theresa May’s Government, want to...set out a better path, one that actually leads to a prosperous, secure and united country.  We can do that, and we will under her leadership.  She should stay.

“Do not doubt that the Prime Minister’s absolute commitment to tackling the injustices is a real one.  And as the Prime Minister also said this week, we are at a turning point for the nation.  Trust that it is us who will take Britain in the right direction.”

Ms Rudd refers to "presentation fails" in the Prime Minister's speech but urges her party and the public to look beyond them to the policies outlined by ministers at the Conservative party conference earlier this week.

In her article Ms Rudd sets out the government's plan for a new immigration system, a commitment to take the lowest paid out of tax and a plan for a new minimum wage. she also says that Brexit must ensure that Britain businesses are not hit by "unnecessary burdens" or labour shortages.

Ms Rudd's assurances that the Government is united under Mrs May's leadership come as the Prime Minister is being urged by ministers to sack Mr Johnson after his perceived disloyalty dominated the Conservative Party conference and, ultimately, led to the prank which saw her handed a P45 on stage.

They have also suggested she should carry out a major Cabinet reshuffle to get rid of “duds” and bring in ambitious young MPs who could one day succeed her.

Downing Street has made clear that the Prime Minister will not be resigning and Cabinet members have rallied around her to offer their support.

Greg Clark, the Business Secretary, praised Mrs May’s “guts and grace” in battling through her speech as she lost her voice. Charles Walker, vice chairman of the 1922 Committee, said Mrs May was like “forged steel” and doing “an outstanding job”.

Mrs May spent today at home in her Maidenhead constituency recovering from the cold that ruined her speech, and will today carry out her regular Friday surgery today before spending the weekend at Chequers and in Maidenhead preparing for the new parliamentary session.

On Wednesday the 1922 Committee of backbench Tory MPs will meet for the first time since the party conference for what could be a pivotal moment for Mrs May’s future.

Geoffrey Clifton-Brown, an executive member of the backbench 1922 Committee, said Mrs May “needs to demonstrate leadership”.

He said the party was “a little bit in limbo” and the speech “could have been much stronger”.

David Mellor, the former culture secretary, described Mrs May as a “dead woman walking”, while One backbencher told the Telegraph Mrs May is “no longer seen as credible or competent”.

Explaining the plans to confront Mrs May this weekend, the MP added: "It has to be all or nothing. "We can't have a situation where a few go public with their criticism and the rest fade away. There is a small window of opportunity here, more people are coming forward.”

The rebels do not intend to trigger a formal no confidence vote in Mrs May - for which 48 MPs would need to write to the 1922 committee to express no confidence in her - but instead want her to accept that the game is up.

Mr Vaizey, speaking to BBC Radio Oxford, said: "I think there will be quite a few people who will now be pretty firmly of the view that she should resign.

"I didn't predict Brexit, I certainly didn't predict the election result.But the Tory Party conference was a great opportunity to reboot the party and therefore reboot the country to give it a clear sense of direction and that didn't happen. So yes, I am concerned."

The rebels include both Remainers and Leavers and have avoided communicating via messaging services such as WhatsApp to avoid names being leaked. Instead they are ringing round colleagues to garner support.

Mrs May is considering revealing the Conservatives’ autumn budget plans as early as next week as part of a concerted fightback following the party conference fiasco.

The Treasury is said to approve of the idea of road testing policies before they are announced, following the about-turns on National Insurance contributions after the spring budget and social care in the Tory manifesto, both of which were sprung as surprises.

MPs return to Parliament on Monday in what will be a crucial week for Mrs May. Brexit talks resume on Monday, then on Tuesday she will chair her first Cabinet meeting since the conference.

Mrs May will also face Jeremy Corbyn at Prime Minister’s Questions on Wednesday and will introduce a Draft Bill to put a cap on energy prices.