Ten conservative MPs are vying to become Britain’s next Prime Minister with Brexit supporter Boris Johnson stepping out as the current favourite to succeed Theresa May after her recent resignation from the top job. 

Despite announcing two weeks ago that she will resign as Conservative Party leader on June 7, Ms May will remain “caretaker” Prime Minister until her successor is announced on July 22.

Mr Johnson, the former London mayor and former foreign minister, is the presumed frontrunner. He’s been a vocal opponent of Ms May’s Brexit deal.

Labour MP Ian Murray called Mr Johnson a “greater threat to the Union than the SNP” after he pledged to cut taxes for three million higher earners in a move that would cost 9.6 billion pounds ($175 billion) a year.

Mr Johnson’s successor Jeremy Hunt has been confirmed as the second favourite, describing himself as the best negotiator to deliver Brexit.

Mr Hunt said he was the best person to break the Brexit impasse and described himself as the most experienced candidate.

He claimed to have “delivered the Olympics” and “negotiated peace talks in Yemen”.

Foreign secretary Jeremy Hunt launches his bid for Tory leadership. Photo: Getty

Up against Mr Johnson and Mr Hunt are environment minister Michael Gove, former Brexit minister Dominic Raab, health minister Matt Hancock and interior minister Sajid Javid, the Conservative Party’s 1922 Committee revealed on Tuesday (Australian time).

The other candidates are international development minister Rory Stewart, former minister Esther McVey, former leader of the House of Commons Andrea Leadsom and Conservative MP Mark Harper.

Each candidate required backing from at least eight MPs to enter the race to become the next party leader and ultimately prime minister.

The first round of voting among Conservative lawmakers to begin whittling down the field to two candidates, who will then be put to a vote of party members, will take place on Thursday.

Scottish National Party (SNP) Westminster leader Ian Blackford described the tone of the Tory leadership debate as “utterly horrific”.

“From advocating a hard Brexit, curtailing women’s rights and offering tax cuts to the richest in society, the nasty party is well and truly back,” he said in a statement.

He accused the handful of MPs who are running of focussing on their own party’s fate rather than “working to find a solution from the Brexit chaos”.

Green MP Caroline Lucas said the leadership contest will simply expose the infighting among Conservative leadership hopefuls and ignore “the real concerns of people in Britain”.

“The comments coming from some leadership contenders on how they would get round parliamentary opposition to a No Deal Brexit are deeply worrying, and show a contempt for parliamentary sovereignty and the democratic process in Britain,” she said in a statement.

-with agencies