The Conservative Party is mobilising to replace Theresa May as prime minister.

May has hemorrhaged support among Conservative MPs in recent days after agreeing to delay Brexit and blaming the House of Commons for the crisis in Westminster.

Pro-European Conservative MPs tell Business Insider that a Brexiteer will win the race and are moving to back the "least bad" candidate.

Party officials and senior MPs say that Amber Rudd will be the "kingmaker" in the contest.

LONDON — The battle to replace Theresa May as Conservative leader and prime minister is well underway with pro-Europeans in the party discussing which Brexiteer is "least bad" and should have their support, MPs and Tory officials have told Business Insider.

The prime minister has hemorrhaged support among her MPs in recent days following her decision to delay Brexit and her ill-advised speech blaming MPs for the ongoing political crisis in the United Kingdom.

"I can't think of a single MP who wants her to stick around. It used to be the ERG but moderates are saying it now," a party figure who attended a lunch of "moderate" Conservative MPs this week told BI.

"Wednesday [May's statement] really sealed the deal for many people. It was so divisive."

"Everyone said the prime minister needs to go. Even usually loyal junior ministers were saying it. Nobody thinks she should stick around."

May cannot be forced out until the end of the year under Conservative party rules. However, discussions are underway to pile pressure on her to step down after a disastrous week for her premiership.

Plans to replace her are already developing fast with both wings of the party mobilising behind likely successors.

There is a growing belief among the party's pro-EU MPs that their next leader will be someone who campaigned for Leave in the 2016 referendum, given the overwhelmingly pro-Brexit slant among Conservative members.

In recent days, senior figures in the Tory party's moderate wing have discussed which Brexiteer MP they should endorse in the contest to replace May, amid suggestions that she could resign in the next few weeks.

"There is an acceptance that it has to be a Brexiteer, so for moderates the question is who is the Brexiteer going to be. Or who the least bad one is," one Conservative party official told Business Insider.

Rudd the kingmaker

Work and Pensions Secretary Amber Rudd. Jack Stringer/Getty Images

Moderate Conservatives believe that their preferred candidate, Work & Pensions Secretary Amber Rudd, is not likely to stand. She is hamstrung both by her support for Remain and a tiny majority in the Hastings & Rye seat which the Labour Party is targeting.

However, Rudd is expected to be a "kingmaker" in deciding which Brexiteer becomes party leader.

"It's about who Amber supports ... She is the one that people will follow and say 'what is she doing?'" one said.

They believe that the candidate who Rudd endorses will subsequently get the support of swathes of moderate Conservative MPs, with Environment Secretary Michael Gove seen as one of the more "palatable" options.

"It's so s*** that Amber doesn't have a big majority and Ruth [Davidson, leader of the Scottish Conservatives] isn't down here," they added.

A former Conservative Cabinet minister told BI this week that choosing May's successor "through the prism of whether you are a true Brexiteer" would mean there was a "good chance you end up picking the wrong leader."

They told BI: "Brexit will dominate our politics for the next five years at least. But we need a leader who’s capable of talking about more than that.

"Liz Truss — I don’t necessarily think she will be leader — but she’s developed a real niche as a champion of free markets. People didn’t take it seriously when she started doing it but they respect her now.

"We need more MPs like that."

A senior figure in the Conservative party's moderate wing predicted that the Tories would suffer an exodus of members and spend years in opposition if it elected former Brexit Secretary Dominic Raab as its leader.

Raab, a front runner to succeed May, would represent "the complete end of Cameron modernisation," they told BI.

"We'd never win back the seats we need for a majority like Battersea and Twickenham. We’d lose Richmond Park in seconds. We'd never win back Canterbury with him in charge. The party would be totally lost and end up in opposition. He is so right-wing. I'm no fan of Boris [Johnson] but god I'd rather have him any day.”

Raab gave a speech last week which was widely interpreted as a leadership pitch.

Asked by Business Insider whether he wanted to be prime minister, he said: "never say never."