LONDON — The United Kingdom came one step closer to finding out who its next prime minister will be Tuesday after the ruling Conservative Party chose its final five front-runners in the fight to replace Theresa May.

Boris Johnson, the New York-born former mayor of London, remains the overwhelming favorite to succeed May. He secured the votes of 126 out of 313 Conservative members of Parliament in what was the second round of the internal party election.

Though their chances are slight, four others — all male, and all ministers in May's government — are also still in the running.

Officially, the contest will decide who is the next leader of the Conservative Party. By a quirk of the U.K.'s political system, that person will also become the next prime minister — no general election is needed.

First, Conservative lawmakers in the House of Commons vote in successive rounds until only two candidates remain. These final two enter a runoff decided by some 120,000 Conservative Party members.

May was toppled because she was unable to get her Brexit deal through Parliament. It's far from clear that any of her would-be successors have a workable plan to succeed where she failed.

Here are the runners and riders:

Boris Johnson

His name is Alexander Boris de Pfeffel Johnson, but the former London mayor belongs to that rare club of politicians instantly identifiable by one name: Boris.

Johnson is reviled by critics who brand him a racist and a serial liar, a man whose thirst for power knows no bounds. To his fans, of whom there are plenty, he is perhaps the only British politician with true celebrity star power, a whirlwind of charisma, buffoonish charm and sharp intellect.

Stanley Johnson, father of Boris Johnson, wears a "Back Boris" badge in London last week. Toby Melville / Reuters

Supporters hope these unique gifts represent an elixir for the Tories, who have been on the brink of civil war over Brexit. They believe Johnson can chart a course out of the European Union, stave off populist threats from Nigel Farage's Brexit Party and Jeremy Corbyn's Labour, and ultimately stop the Conservative Party from tearing itself to shreds.

On Brexit, which Johnson spearheaded, he says he wants to renegotiate May's deal and remove the so-called Irish backstop, an insurance clause to prevent a potentially fractious border being resurrected between Northern Ireland and the Irish Republic.

However, European Union officials and European prime ministers have repeatedly insisted that this backstop is not up for renegotiation. Failing that, Johnson has vowed to take the U.K. out of Europe on the current deadline of Oct. 31 — even if no deal has been agreed. Business leaders and analysts warn this could have dire economic consequences and even spark shortages of food and medicine.

Rory Stewart

All but unknown outside political circles until recently, Rory Stewart has enjoyed a remarkable rise during this campaign.

He is an eccentric with a weird and wonderful career that has involved trekking across Afghanistan and writing a book about it, helping to run part of Iraq following the U.S.-led invasion in 2003, smoking opium at an Iranian wedding, and giving a remarkable House of Commons speech about hedgehogs.

In recent weeks Stewart, currently the international development secretary, has popped up all over the county, challenging people to debate him in the street and broadcasting it live on Twitter.

His straight-talking, common-sense style has won him admirers across the political center and even among a few to the left (not that they get a say).

Rory Stewart arrives at 10 Downing Street on Tuesday. Daniel Leal-Olivas / AFP - Getty Images

It's hard to see how he can defeat Johnson, unless the favorite shoots himself in the foot with one of his notorious gaffes. That's because most Conservative members — who get the final say — have said they would back a leader willing to enact a hard Brexit. This is precisely what Stewart says he wants to avoid, a stance that sets him apart from his rivals.

Acknowledging the E.U.'s repeated statements that it will not renegotiate May's deal, Stewart says he says he would try again to pass this plan. It's a piece of legislation that suffered the biggest ever parliamentary humiliation among its four defeats in the Commons. Stewart has also suggested forming a "people's assembly" of citizen representatives to try to break the deadlock.

While still a little way behind Jeremy Hunt and Michael Gove, Stewart appears to have momentum. He gained the most votes between the first and second rounds, almost doubling his total from 19 to 37.

Jeremy Hunt

Hunt is Johnson's successor as foreign secretary but could not be more different in terms of style. Whereas Johnson is catnip for Westminster journalists — always ready to offer a colorful quote, or a picture of him stuck halfway down a zip line — Hunt offers much less in terms of showbiz appeal.

The left-wing tabloid The Mirror described the foreign secretary's performance in a TV debate Sunday as "mild-mannered, polite and boring — as usual."

Jeremy Hunt leaves 10 Downing Street last week. Isabel Infantes / AFP - Getty Images

He speaks fluent Japanese, but made a high-profile blunder when on a visit to Beijing last year, mistakenly telling his hosts that his Chinese wife was Japanese. Until Stewart's rise, he had become the second favorite among bookmakers, behind Johnson.

Though not flashy, he is seen by some colleagues as a safe pair of hands. One of his backers, Amber Rudd, the work and pensions secretary, told The Daily Express newspaper that he is "a man skilled in the art of negotiation rather than the art of bluster" and "a leader who can command respect in Brussels and on the world stage."

He voted Remain in the referendum but now says no-deal would be better than failing to leave the E.U. at all. He too proposes changing the Irish backstop — despite the E.U. saying this is impossible — and vows to send a fresh negotiating team to Brussels. He says he wants to avoid a no-deal Brexit but will go through with that if he deems it necessary.

Michael Gove

This is not Gove's first run at being prime minister. Alongside Johnson, he was one of the main faces of the Brexit campaign that rode to victory in the 2016 referendum.

After that result toppled the then prime minister, David Cameron, Johnson declared he was running to succeed him, with Gove acting as his running mate. However, Gove effectively neutered this bid by announcing his own push for power.

Rory Stewart and Michael Gove talk near the Parliament grounds on Monday. Henry Nicholls / Reuters

It was believed that many Conservative lawmakers would not support Johnson without Gove by his side — and the episode ultimately ended both their chances, with May ultimately being crowned unopposed.

This time, the now environment secretary is seen by some commentators as a powerful candidate, someone who supported Brexit during the referendum but who appears reluctant to gun for a risky no-deal Brexit on Oct. 31. His campaign hit rocky ground earlier this month after he admitted using cocaine when he was younger.

On Brexit, Gove claims he could secure a new "digitized" version of the backstop, while warning that the country should prepare for the no-deal cliff-edge.

Sajid Javid

The home secretary impressed political commentators with a slick campaign video that emphasized his family roots and how they have shaped his political outlook.

I got into politics because I wanted to give back to our country, which has given me so many opportunities. I'm proud to be able to share my story with you. Check out my campaign video and join me at https://t.co/idVRwMVc79 pic.twitter.com/L7cypOHNmA — Sajid Javid (@sajidjavid) June 11, 2019

His father was a bus driver who came to Britain from Pakistan in 1961 with just £1 in his pocket. Before going into politics, Javid worked as a managing director at Deutsche Bank and reportedly made £20 million (around $25 million) during that part of his career.

Sajid Javid launches of his campaign for the Conservative Party leadership in London last week. Toby Melville / Reuters

Although he supported remaining in the E.U. in the referendum, after the result, he said, "We're all Brexiteers now."

He is another candidate who wants to renegotiate the Irish backstop. He has also called for ramping up no-deal preparations to show Europe that Britain is serious about this drastic scenario — and if need be, follow through with that threat.

Javid scraped into the next round with just 33 votes, the minimum required. The sixth challenger, the former Brexit secretary, Dominic Raab, fell just short with 30 votes, and was eliminated.