LONDON (NYTIMES) - Last week, for the first time in six months, Prime Minister Theresa May enjoyed a few hours of sweet vindication in her efforts to allow the United Kingdom to leave the European Union. She had passed the night in white-knuckled negotiation, and by sunrise was able to announce the beginning of talks that would lay out a path to a controlled departure.

Another politician would have crowed a little, or luxuriated in the moment. But not May. She landed from negotiations in Brussels and her motorcade rushed straight from the airport to a neighborhood of neat, redbrick houses, where she attended a gathering of Alzheimer's patients, followed by a fundraiser for a children's hospice and a Christmas tree festival. No reporters were invited. She showed up because she had promised to be there.

The same old-fashioned, unglamorous, dutiful approach has guided May, 61, throughout her struggle to guide the country's withdrawal from the EU, known as Brexit. There are no victory laps. Instead she ploughs forward, scrambling to her feet after each roundhouse blow, most recently on Wednesday night, when Parliament secured the right to approve - or veto - her final deal.

She has been undermined by her own Cabinet ministers, derided as pitiful in Brussels and mocked in the news media as a "dead woman walking". Though the only other woman to hold the post of prime minister, Margaret Thatcher, was able to transcend her gender, May has been hemmed in on all sides by stereotypes - first criticised as a humourless headmistress, not human enough to be likable, and then as too human, and therefore weak.

"When she decides to do something, she really is capable of putting herself through a lot," said Alasdair Palmer, who worked as a speechwriter for May for a year when she was home secretary, the Cabinet official responsible for policing and security.

"Most people would have thought, 'This isn't worth it, it's so horrible,'" he said. "She has decided she has to do it, that it's in the best interests of the country. I think she has put her interests to one side. I don't think she is particularly interested in power for its own sake." May is said to stick closely to written scripts during negotiations, and hardly projects warmth. But European leaders, too, have watched closely with "a combination of sympathy and alarm" as she withstood a battery of domestic political blows, said Elmar Brok, a German politician and chairman of the European Parliament Committee on Foreign Affairs.

"Many of us felt personally very sorry for her," he said. "It is impressive how she takes this, how she takes it and she does not give up. Not many would do this. They would say, 'Please, take this rubbish yourself.' She has the stamina to move forward. That is impressive." May lacks many of the qualities that draw a person into politics. She does not enjoy the public spotlight, or have a vision she yearns to share with the country. In a political environment that demands social ease and boundless intellectual confidence - the "tranquil consciousness of effortless superiority" once ascribed to Oxford's Balliol College by one of its famous alumni - she is formal, controlled and extremely private.

In some part, this reflects her modest origins. She was the only child of a small-town vicar, the granddaughter of two ladies' maids and the great-granddaughter of a butler. Asked by a radio host to recall the songs that most powerfully evoked her youth and adolescence, she selected, among others, a hymn published in 1707, recalling that sometimes, "if my father, mother and I were just alone in the church, we would just kneel down and sing." When pressured to speak publicly about her inner life, May snaps shut like a purse. Katie Perrior, who served as her director of communications, after she became prime minister, recalls coaxing May to tell reporters about her family's painful experience of infertility - a rival had nastily raised her childlessness as a flaw - and being met with blank incomprehension.

"She didn't really understand why anyone would be interested in this," Perrior said. "She said, 'They just want me to do a good job, they want me to run the country.' I said, 'They want to know that the way they hurt, you hurt in the same manner.' She said, 'Well, I do, but I don't have to broadcast it.'" Eventually, Perrior gave up, having learned none of the details of May's biography herself. "She didn't share anything with anyone," she said. "I respect that entirely, but it makes it hard because even her Westminster friends don't know her. She doesn't seem to beg for friendship in that way."

Her sense of duty, however, is the stuff of legend: She adores dogs, and toyed with the idea of bringing a chocolate Labrador puppy with her into No. 10 Downing Street, but decided against it because, with a heavy travel schedule as prime minister, she would not have had time to walk it herself, wrote Tim Ross and Tom McTague in "Betting the House", a chronicle of May's decision to call an early general election.

"In some ways, she's old-fashioned English in an era where being old-fashioned and English is no longer acceptable," said Philip Cowley, a political scientist at Queen Mary University of London.

At first, the voters and Britain's influential tabloids regarded her as an iron lady in the mould of Thatcher, but that impression faded rapidly. May, who had opposed Brexit during the referendum campaign, squandered much of her political capital when she called that early general election. She proved a poor campaigner and the decision backfired spectacularly, resulting in a hung Parliament.

"It took a few moments for it to sink in, what was really going on," she told a radio interviewer who asked how she felt about the result. "My husband gave me a hug." She confessed to weeping. "I felt, I suppose, devastated really," she said.

Critics said she had placed too much faith in her aides to define the campaign, and some put this down to a lack of intellectual confidence. Palmer, her former speechwriter, said May was "keenly aware of her limitations".

"She does know she is sort of slightly out of her depth," he said. "She is not stupid, but to be a prime minister, even to be a minister, you need to have some of the abilities of a first-class lawyer. You need to read through large amounts of material. She can't do that quickly. It takes her a long time; she likes to read carefully."

In October, she climbed onto a podium to deliver a keynote speech intended to restore confidence to her shaky party. But halfway through, as if in an anxiety dream, her voice faded to a rasp, so that she was barely able to produce sound. She was left to struggle for a half-hour, alone on stage, before a hall packed with critics.

Rosa Prince, a political journalist and the author of "The Enigmatic Prime Minister", a mostly admiring biography of May published in February, updated it for the fall to include her breathtaking reversal of fortune.

"It's almost Shakespearean - all I see her doing now is hanging on in there," Prince said. "She's now got this aura around her, where she is wounded and limping along, and there is a stench around her of failure."

Political death comes quickly for Tory leaders, and many said May's days were numbered. Her party's backbench lawmakers gather regularly to form the 1922 Committee - known, ominously, as "the men in gray suits" - which can end the career of a Conservative prime minister overnight with a no-confidence vote. She was called a "wounded she-elephant," and "one crisis from the exit".

One political commentator said she had "as much chance of making it unscathed past Christmas as a tray of pigs in blankets." May's survival remained a matter of speculation - until Monday, when she walked into the Commons to report on the beginning of Brexit talks. Her party had overtaken Labour in a closely watched poll for the first time since the snap election, and lawmakers, one by one, praised her resilience and grit. May was loose and unhurried - once again a woman in control.

When backbench lawmakers interrupted her presentation with the adenoidal mooing so beloved by British politicians, May looked up quizzically, with a tiny, ironic smile, and waited for it to die down. They were no longer her tormentors.

Even the ritual attack by her opponent, Labour's Jeremy Corbyn - "the prime minister has scraped through phase one of the negotiations, scraped through after 18 months" - came off as a grumpy compliment. The prime minister spoke with brisk precision, as if she were squeezing the words from a pastry bag: "We are going to leave, but we are going to do so in a smooth and orderly way." Her respite would not last long. By Wednesday, rebellious lawmakers in Parliament had hemmed her in by demanding a say on the final deal.

John Peters, 49, has observed her travails from the Anchor, a pub in May's home constituency of Maidenhead, which fills up as a nearby Mars bar factory empties. He said he did not trust politicians as a class but had a soft spot for May, who he said had been shoved by her Brexiteer rivals into a job no one else wanted.

"She may not want to do it, but it's been foisted upon her," he said. "She hasn't had an easy ride, has she?" A deep, biting cold had set in, and you could see your breath sitting at the bar. Peters guessed that as soon as a trade deal was complete, probably in the spring of 2019, the prime minister would be handily removed, replaced by a younger, more politically dexterous man.

"When she's done the dirty work, she will go," he said. "It's like someone running past a line of soldiers - you either get through, or you get shot. She'll be getting fire from all sides. And she's basically on her own."