Britain's former Foreign Minister Boris Johnson listens to delegates in the United Nations Security Council on Somalia. File picture: Richard Drew/AP
Britain's former Foreign Minister Boris Johnson listens to delegates in the United Nations Security Council on Somalia. File picture: Richard Drew/AP
Dominic Raab arrives for a cabinet meeting at 10 Downing Street in London. File picture: Matt Dunham/AP
Dominic Raab arrives for a cabinet meeting at 10 Downing Street in London. File picture: Matt Dunham/AP
Britain's Foreign Secretary Jeremy Hunt arrives for a cabinet meeting at 10 Downing Street in London. File picture: Matt Dunham/AP
Britain's Foreign Secretary Jeremy Hunt arrives for a cabinet meeting at 10 Downing Street in London. File picture: Matt Dunham/AP
Britain's Home Secretary Sajid Javid is seen outside 10 Downing Street. File picture: Hannah Mckay/Reuters
Britain's Home Secretary Sajid Javid is seen outside 10 Downing Street. File picture: Hannah Mckay/Reuters
Britain's Secretary of State for Health Matt Hancock is seen outside 10 Downing Street. File picture: Hannah Mckay/Reuters
Britain's Secretary of State for Health Matt Hancock is seen outside 10 Downing Street. File picture: Hannah Mckay/Reuters
Britain's Secretary of State for International Development Rory Stewart is seen outside 10 Downing Street. File picture: Hannah Mckay/Reuters
Britain's Secretary of State for International Development Rory Stewart is seen outside 10 Downing Street. File picture: Hannah Mckay/Reuters
Britain's Environment Secretary Michael Gove leaves the BBC, after appearing on the Andrew Marr Show, in London. Picture: Simon Dawson/Reuters
Britain's Environment Secretary Michael Gove leaves the BBC, after appearing on the Andrew Marr Show, in London. Picture: Simon Dawson/Reuters
Andrea Leadsom, the former Leader of the House of Commons, leaves a cabinet meeting at 10 Downing Street in London. File picture: Matt Dunham/AP
Andrea Leadsom, the former Leader of the House of Commons, leaves a cabinet meeting at 10 Downing Street in London. File picture: Matt Dunham/AP

London - Brexit is expected to dominate the debate when the two-stage election contest to succeed Prime Minister Theresa May as head of Britain's Conservative Party formally begins after the closing of nominations late Monday.

The Conservative Party's 313 lawmakers will hold a series of votes over the next two weeks to narrow the field down to two candidates. The new party leader will then be selected by some 125,000 party members and is expected to take the reins as prime minister.

The party changed its rules last week in a bid to eliminate some weaker entrants before voting begins. The new rules require all candidates to have the backing of at least eight Conservative lawmakers to enter the contest; they also raise the vote thresholds at subsequent stages.

The new rules could eliminate five of the 11 party members who had declared their candidacy by last Thursday, according to an analysis by the political website Conservative Home.

The first ballot of lawmakers is scheduled for Thursday, with further ballots on June 18, 19 and 20 if needed.

Pro-EU moderates in the party hope to stop the election of the clear favourite, former foreign secretary Boris Johnson, who was backed by 32 per cent of members in a Conservative Home survey in April.

Below, a summary of the positions on Brexit and related issues adopted by Johnson, Jeremy Hunt and the other main candidates:

* BORIS JOHNSON, 54, told a prospective Conservative voter in his campaign video that Britain will "come out [of the EU], deal or no deal, on October 31," referring to the delayed Brexit deadline that May agreed with Brussels.

The gaffe-prone Johnson rejected May's deal and accused her of weak negotiating. But like May, he has styled himself as a guardian of the will of the 52 per cent of British voters who chose Brexit in a 2016 referendum. He is popular with right-wing and eurosceptics, but some accuse him of promoting inaccurate or misleading claims as the co-leader of the Vote Leave campaign in 2016.

* DOMINIC RAAB, 45, is one of Johnson's rivals for the support of Conservative eurosceptics. The former Brexit secretary has promoted his "plan for change, and a fairer Britain." The country must show "unflinching resolve to leave" the EU, with or without a withdrawal agreement, Raab wrote in the Mail on Sunday.

* JEREMY HUNT, 52, is Britain's current foreign secretary. Hunt is a leading centre-ground candidate, standing as a former entrepreneur "to unleash growth and make our economy competitive post Brexit." His campaign calls him a "trustworthy leader, who is prepared to tell the truth and who, crucially, is respected on the world stage."

* MICHAEL GOVE, 51, says he is "ready to unite our party, ready to deliver Brexit and ready to lead our great country." He has suggested Brexit could still be delayed beyond October 31. Gove is criticized by some Conservatives after he switched from supporting Johnson in the 2016 Conservative leadership campaign to attacking the credentials of his friend and former ally.

* SAJID JAVID, 49, the home secretary, has positioned himself as a centre-right "One Nation Conservative." On Wednesday on Twitter, he said the party must "deliver Brexit but do so much more." He saw "the harsh edge of discrimination and exclusion" during his childhood in Britain, saying he wants to "build a nation where nobody has to experience that in the future."

* MATT HANCOCK, 40, the health secretary, is the youngest candidate. "I believe that we must build a world for future generations, not just for our short term needs," he tweeted this week.

* ANDREA LEADSOM, 56, another Brexiteer, has vowed to provide "the decisive and compassionate leadership our country needs." Leadsom said she resigned as May's leader in parliament last month because she no longer believed that May's approach would "deliver on the referendum result."

* RORY STEWART, 46, has vowed not to serve under Johnson or accept a no-deal Brexit. Like Hancock, the international development secretary has presented himself as a no-nonsense, goal-oriented candidate.

dpa