The Prime Minister will challenge Conservative MPs should they make an attempt to force a vote to oust her, The Sunday Times reports.
In an act of defiance, Mrs May declared she would be content to “win by one vote” which means Tory rebels would need 159 MPs to boot her out – more than three times the 48 required for a vote of no confidence.
Her stark ‘back me or sack me’ warning comes as she faces a tough week of crunch Brexit talks with the cabinet – amid claims six senior ministers are actively plotting against her.
Mrs May has vowed that should Brexiteers attempt to stop the Government pursuing a Norway-style deal – which would keep Britain closely tied to Brussels on the sale of goods – then they will have to remove her altogether.
If Mrs May is ousted, 20 MPs are preparing to run for leader by actively recruiting backers, the publication reports.
These include Home Secretary Sajid Javid, Environment Secretary Michael Gove, Health Secretary Jeremy Hunt.
A senior Conservative MP said: “Theresa thinks that if there is a vote of no confidence she has to win by only one vote.
“It’s effectively saying to people, ‘Come and have a go if you think you’re hard enough’.”
Downing Street staff fear Mrs May’s publication of the white paper revealing Britain’s negotiating stance on Brexit and Friday’s cabinet meeting will trigger a revolt against her.
Though a senior source said: “She’s not going anywhere.”
Over the weekend, 36 MPs demanded Mrs May “get tough” with Brussels and “demonstrate courage and leadership” and fight a hard Brexit.
According to The Sunday Times, the white paper will state that the UK does not want to stay in the single market, customs union or take orders from Brussels post-Brexit.
Though officials say Mrs May will propose a Norway-style option with her cabinet this week, which will keep the nation shackled to the EU rules on the sale of goods, grant EU citizens the right to travel to the UK to work and live and give a greater role to the European Court of Justice than Brexiteers are likely to tolerate.
Meanwhile, treasury officials are pushing Mrs May to get a six-month extension on Article 50 so Brexit can be delayed so Britain can scoop the best deal possible.