These Conservative Party members, seen in Exeter, England, on June 28, will be among those 165,000 people who will choose the U.K.’s next prime minister.Dylan Martinez / Reuters

Britain’s next prime minister will govern a country of 66 million, but the pool of citizens deciding who that individual will be is decidedly smaller: 165,000.

The reason for that is simple: When Theresa May resigned from office in May, citing her failure to get her Brexit deal through Parliament, she did so as the leader of Britain’s Conservative Party. As a result, the contest to replace her is about choosing the next leader of the Conservatives—a decision that ultimately falls to the party’s members. This “selectorate” represents less than 1 percent of the broader U.K. electorate of 46 million. Their decision, however, will affect the entire population: As the leader of the ruling party, the winner will automatically succeed May as prime minister.

So who are these voters? On paper, they are the dues-paying members of the Conservative Party. A closer look reveals a group that is whiter, older, more male, and wealthier than the rest of the country. Yet perhaps the biggest way in which they differ from their compatriots is over the one issue that matters these days: Brexit. Tory members are committed to seeing Brexit delivered by the end of October, whether or not Britain has a deal with the European Union managing its withdrawal. And unlike the rest of the country, most of them are willing to see that happen at virtually any cost. The majority of the British public view a no-deal scenario—where the country would leave the bloc without any agreement on a litany of core issues such as tariffs, border management, pharmaceutical regulation, and the like—and the adverse impact it would have on the country’s economy as a bad outcome.

To understand the makeup of the Conservative Party, it helps to look at the numbers. Though 42.3 percent of the U.K. electorate voted Conservative in the last general election, the overall membership of the party is notably smaller: Approximately 165,000 people are card-carrying Conservatives who pay an annual fee of £25 ($31) to maintain their membership. (By contrast, the opposition Labour Party boasts more than half a million members who pay as much as £51 annually in dues. The Liberal Democrats have approximately 105,000 members, most of whom pay £36 annually.)

These members “aren’t particularly representative of British society in the 21st century,” Tim Bale, a professor of politics at Queen Mary University of London and a co-author of the forthcoming book Footsoldiers: Political Party Membership in the 21st Century, told me. He noted, for example, that 97 percent of Tory members identify as white—a marked contrast from the general population, of which 15 percent is of an ethnic-minority background.

Diversity isn’t where the divergence stops. According to the Party Members Project, a research initiative of Britain’s largest political parties conducted by Bale and the academics Paul Webb and Monica Poletti last year, the Tory rank and file tend to be older. The average age is 57, which is higher than the U.K. average age of 40, though not that different from the average Labour and Liberal Democrat ages of 53 and 52, respectively. They also tend to be more male: Seven out of 10 Tories are men (a gender imbalance that is even worse in Parliament, where female lawmakers make up 21 percent of the Conservative benches—though the party is the only one that has elected two women as leaders, Margaret Thatcher and May).

In terms of education, 42 percent of Conservatives hold a university degree—a figure lower than the all-party average of 51 percent, but on par with the wider U.K. average. In general, Tory members tend to be concentrated in the more economically prosperous southern half of England and are of predominantly private-sector career backgrounds. (Issues of diversity are not exclusive to the Conservative Party, however. In general, Bale said that party membership in Britain across the political spectrum tends to skew more toward middle-class, middle-aged voters.)

But perhaps the starkest difference between Conservatives and the rest of the U.K. electorate is their position on Brexit. The average Tory member wants Britain to leave the European Union as soon as possible, with more than half willing to countenance damage to the country’s economy and the unraveling of the union with Northern Ireland and Scotland just to see it happen—a remarkable statement from members of what is officially the Conservative and Unionist Party. While 28 percent of the country overall supports leaving the EU without a withdrawal agreement, a recent survey by the British polling firm YouGov found that a majority of Conservatives would support this outcome. More than half of Tory members polled said they would vote for the next party leader based on that person’s Brexit plan alone.

Ordinarily, one party’s vision for the country wouldn’t be so consequential, as elections in Britain are rarely decided on by the members of a single political group. In theory, the person who becomes prime minister is decided on through a general election, in which the leader of the party with the largest share of seats—and, therefore, the mandate of the broader electorate—enters Downing Street. In recent British history, however, there have been instances of prime ministers taking office without an election: May herself replaced David Cameron in 2016, and Gordon Brown took over from Tony Blair in 2007.

In both of those instances, though, party lawmakers—representing their entire constituencies—chose the new leader of the ruling party, and thus the prime minister. This contest marks the first in which party members will get to pick who ultimately wins. Changes to both the Labour and Conservative Party rules in past years have given their members a greater say in deciding who becomes leader.

That’s how Britain arrived at this juncture: May’s resignation sparked a leadership contest in which Conservative members of parliament whittled down a list of 13 candidates to two, Boris Johnson and Jeremy Hunt. The fact that the winner will be decided by the Tory members themselves is not lost on either candidate.

“It only becomes problematic when the leadership contest is being held in the governing party and therefore the leader becomes prime minister,” Bale said. “It’s no coincidence that this is the first time it’s ever happened because, generally speaking, we don’t see parties hand over their leadership in government.”

That only a small subset of the U.K. population will decide on the country’s next leader has prompted some to suggest that the rules governing leadership selection need revising. “Bluntly, [the Conservative Party] is now a party of old, rich people,” Nick Boles, the former Conservative lawmaker who resigned from the party this year to sit as an independent in Parliament, told an audience at the London-based Institute for Government on Tuesday, adding that the party “should not see it as their role to represent only the view of Conservative Party members in the governance of our country.”

In response to a critical column alleging that the leadership contenders had abandoned all sensibilities to appeal to their base, Hunt tellingly didn’t dispute the claim.

“Thanks for the criticism,” he tweeted, before adding: “That’s another 10,000 Tory votes.”

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