LONDON — With David Cameron facing calls to quit and Boris Johnson accused of bungling his big chance, Britain’s steely Home Secretary Theresa May is fast emerging as the big winner of the Conservative Party’s poisonous civil war over Brexit.

Unlike her main party rivals, May has largely kept out of the fray after declaring early for a vote to Remain, escaping much of the backbench Tory fury directed at the prime minister and Chancellor George Osborne.

In her one major intervention of the campaign, the home secretary gave a defiantly hostile speech on Europe while still urging a vote against Brexit, positioning herself in one observer’s eyes as “the chief Euroskeptic for In.”

And yet by backing the government, May has avoided a potentially toxic association with UKIP and elements of the hard-left in the Out camp.

In Westminster parlance, she’s one of the few big beasts “having a good campaign.”

“She’s in a strategically good position, but that is just a by-product of the type of politician she is,” said one Tory minister. “It’s just part of her nature — all this shouting across the aisles is anathema to her.”

She’s the sensible woman getting on with the job, while the public schoolboys squabble over Europe. It’s not a bad image to cultivate ahead of the Tory leadership contest, which Cameron hopes to delay until 2019.

But can she be leader? And what type of prime minister would she be?

Unlike Osborne and Johnson, her main rivals in the race to replace Cameron, May has no Westminster “operation.” There are no Mayite MPs organizing on her behalf. Instead, May has hired an official spokesman on a civil service contract, the respected former Sky News deputy political editor Joey Jones.

Her admirers say this is partly because she knows she cannot beat Osborne in the game of Westminster patronage, or compete in the popularity stakes with Johnson. Indeed, she holds the former London mayor “in disdain,” one of her ministerial colleagues said.

“They don’t like that Theresa will say to them directly that their latest hair-brained scheme isn’t going to work” — A Theresa May ally on Number 10

The only way she can win is on competence — and that means not messing up.

She is already Britain’s longest serving home secretary in over 50 years and there has yet to be a major terrorist incident or increase in crime on her watch.

Respected, but not well liked

A former Downing Street adviser who witnessed direct clashes between Number 10 and May’s Home Office said that she was “always highly rated” by Cameron, who promoted her to home secretary on entering government.

“That [job] has been bit of a graveyard for careers over the years — people not being able to cope with it,” the former aide said. “There’s definitely respect for what she has done.”

However, the relationship between May and Cameron is hardly warm. A close ally of Cameron who asked to remain anonymous said that Number 10 was “terrified” of her. But the relationship is better than it was during the last parliament when May’s team regularly clashed with Number 10.

The former Downing Street aide said: “The operational style — the way that her spads [special advisers] operated — it was a sort of a bunker-ish mentality, that involved lots of briefing against other departments and Number 10.”

There were also times when May’s brusk tone annoyed her colleagues. “I remember a couple of Cobra [the government’s emergency Cabinet Office Briefing Room] meetings when Theresa did not hide her irritation with other ministers,” the former Downing Street aide said. “There would be tutting and rolling of eyes, particularly to more junior ministers.”

The source also said there was high-level “irritation” with the leadership speculation around May.

“Most other ministers are able to stamp on it very quickly so it doesn’t take on a life of its own. Her team did not do that. I don’t think it did her any favors. It just makes her distrusted and disliked by her colleagues.”

Overall, the aide said, May is “incredibly well respected, but not liked. The opposite of Boris.”

Much of the anger, May’s supporters claim, is because Number 10 cannot control her. One of her closest allies, speaking on condition of anonymity, said: “What I never understand about this was why they want to control her? She’s completely loyal, doesn’t make mistakes. Why would you want to tackle her?”

“It’s Number 10’s problem — they are scared of her strength. They don’t like that Theresa will say to them directly that their latest hair-brained scheme isn’t going to work.”

Record of reforms

Despite a reputation as a fierce Conservative, on paper her record as a liberal reformer is long. She has overseen a reduction in crime while cutting 18 percent of the police budget, curtailed stop-and-search powers despite resistance from Number 10 and introduced the world’s first law to tackle modern day slavery.

She was also crucial in supporting the victims of the 1989 Hillsborough soccer stadium disaster, publicly eviscerated the Police Federation over corruption and introduced directly elected police and crime commissioners.

Her reputation remains, though, one of administrative competence rather than reformist zeal.

When May arrived at the Home Office she told staff her priority was to return the position of home secretary to its proper status as one of the four great offices of state, alongside the foreign secretary, chancellor and prime minister.

In this she sees herself in a similar position to a FTSE 100 chief executive, said a former aide. “The one thing that drives everything for her is that she sees herself as being elected to do a job,” the aide added. “She sees it as a duty. She gets most upset when people aren’t doing their jobs properly.”

There are shades of Margaret Thatcher in this, and in her ferocious work ethic. Unlike the current prime minister, no one could accuse May of ever “chillaxing.”

Up before 7 a.m, she is in the gym for 7:30 a.m before getting into the department some time after 8 a.m. At this point, she dumps three or four of her official government red boxes crammed with Home Office documents completed the night before.

“She’s the only woman I know who’s got a decent pair of balls. I can’t help but admire somebody like that” — Hillsborough campaigner Margaret Aspinall

“Sometimes there will be things in the red box that will make her go pink with fury that she will want answers from civil servants within the hour,” one of her former advisers said.

At around 11 a.m she sets an hour aside for signing warrants, granting police and the security services permission to monitor suspects.

After a working lunch and either parliamentary duties or work in the department a second dose of warrants arrives on her desk at around 7 p.m. She usually arrives home at around 10:30 p.m — when she often calls her closest aides — to start work on the next day’s red boxes, finally getting to bed between 1 a.m and 3 a.m.

Some of May’s critics say she is overrated and too reliant on her advisers, hard work and caution. May’s allies believe she has an instinct for fairness which separates her from her bully boy rivals, Cameron, Johnson and Osborne.

Campaigner for justice

May has won some unlikely supporters by getting involved in high profile miscarriages of justice.

Margaret Aspinall has campaigned for justice for 27 years on behalf of the victims of the Hillsborough stadium tragedy when 96 Liverpool fans were crushed to death. In April the victims’ families finally received justice when a coroner’s court ruled they were unlawfully killed, ending the slur that the fans were to blame for the tragedy.

Aspinall said she believes May’s intervention changed everything. “For the first time speaking to a home secretary I felt someone was actually listening to what I had to say. Everything she promised me she has fulfilled. To get that from the home secretary after 25 years was remarkable.”

Aspinall was also impressed by May’s strength. “She’s the only woman I know who’s got a decent pair of balls. I can’t help but admire somebody like that. She’s not afraid to say what she thinks.”

May also has a fan in Janis Sharp, the campaigning mother of Gary McKinnon, an Asperger’s sufferer who was wanted in the United States for hacking U.S. government computers. After a 10-year battle May intervened in 2012 to block his extradition, sparking fury in Washington. “What I like about her is she says what she thinks,” Sharp said. “She’s very self-assured and brave.”

The height of May’s power came in a 2014 speech to the Police Federation, the unofficial police trade union. Following a series of scandals, May tore into rank-and-file officers, denouncing police corruption, racism and their “contempt for the public.” The speech was greeted with silent shock in the hall.

“She could be the sort of candidate who emerges from a crowded field and people would turn to her in relief” — British cabinet minister

Some believed this toughness would see her back Brexit in the referendum, although those closest to her always insisted she wasn’t an outer. One night over dinner, May said that she could not back Brexit because of the economic risks, according to an ally who was there. May had worked in the Bank of England before going into politics.

“She said she could not look back in her old age and say that she was involved in something that meant people weren’t able to look after their families because the economy crashed,” the ally said, requesting anonymity.

Deciding against Brexit left many questioning whether the 59-year-old May was ruthless enough to win the party leadership, with Johnson hoovering up support among the Eurosekptics.

Cameron’s closest advisers interviewed for this article said the consensus in Number 10 was that she could not beat Johnson in a straight runoff.

Yet she remains ahead of Johnson in the leadership race, according to the latest poll of activists by the influential Conservative Home website.

According to the minister who spoke to POLITICO, it is still “definitely possible” May can become prime minister but she needs to do “a lot of work” to win over MPs.

“She could be the sort of candidate who emerges from a crowded field and people would turn to her in relief. Especially in a field where Boris gains momentum among MPs,” he said. But the minister added, in the end, “she will only get it if others perform badly … and she probably knows this.”

To be still in the race after six years in the Home Office is an achievement in itself. If she’s still there after the referendum nobody would count her out.

At the end of the Police Federation conference speech this year she raised a few eyebrows after refusing to say whether she would be returning as home secretary in 2017. Perhaps she has her eyes on something a little higher.

While all around her are losing their heads, May alone appears to be keeping hers.