Sources close to the Prime Minster have told the Sunday Express she “found out who her friends are” during the rebellion over the EU Withdrawal Bill, when pro-EU Tory colleagues voted against a Government three-line whip on Brexit.
One impeccably-placed insider said the defeat made Mrs May realise that her support in the party lies with the Brexiteers, not the Remainers.
They said: “Theresa found out who her friends are during that defeat and realised that most of the support, both inside and outside the party, lies with Brexit.
“Theresa genuinely sees herself as a public servant carrying out the people’s will and has lost a degree of respect for those who keep trying to reverse the referendum result.
“She genuinely wants the best for Britain and to make the most of the opportunities ahead.”
Determined to fulfil her promise to secure a “deep and meaningful” post-Brexit partnership with the bloc in the form of a bespoke free trade agreement, Mrs May has told colleagues she is willing to “walk away” during the trade talks, which begin formally in March.
A reliable source said: “Many questioned why Theresa didn’t walk away during phase one of the talks, when Arlene Foster’s intervention looked set to put the kibosh on everything.
In the end she didn’t need to because the EU came running, finally realising what they were set to lose.
“But there is a sense that Theresa is not ruling it out if the trade talks hit a similar stalemate.
“That is the ace in her back pocket and having put millions of pounds on the table, she is in a strong position to walk away.”
Under the premise that “nothing is agreed until everything is agreed”, Mrs May has insisted there will be no transitional deal with the EU unless the UK settles its final trading relationship with Brussels by October.
This opens the door to her being able to withdraw Britain’s offer to pay the EU up to £39million until 2021.
Mrs May’s Cabinet is still thrashing out the UK’s preferred end state.
Leading Brexiteers Boris Johnson and Michael Gove believe they are winning the battle for a “divergent” EU withdrawal rather than the closer alliance advocated by Remainers Philip Hammond and Amber Rudd.
Mrs May told a 10-strong Brexit “war Cabinet” of senior ministers before Christmas that the Government must “aim high” by bargaining hard for the best possible deal rather than accepting what the EU is currently prepared to offer.
Brexit Secretary David Davis last week warned the EU negotiations were set to “turn nasty”, adding: “Get ready for thunder and lightning.”
Financial services could be an area where splits emerge between the 27 remaining EU members.
Mrs May was cheered last month by comments from Polish and Italian prime ministers Mateusz Morawiecki and Paolo Gentiloni indicating a willingness to consider a deal that covers services.