LONDON -- Gina Miller is paying the price for going to court.

The financial entrepreneur says she has received death threats and racial and sexual abuse since she won a High Court ruling forcing the British government to seek Parliamentary approval before leaving the European Union. She's hired bodyguards and made "different arrangements" for her children at school.

"It's turned into a poisoned chalice if you like," Miller told The Associated Press as she prepared for the Supreme Court to begin hearing the government's appeal on Monday. "But I'm still determined that I'm carrying on with this. I feel that if I didn't do it, nobody would be asking the questions I'm asking."

The EU exit, or Brexit, is only the most recent battleground for Miller, 51, who was born in the former British colony of Guyana but has lived in the U.K. since childhood. She decided not to pursue a legal career because of sexism. Potential investors dismissed her because of her gender. A campaign she led for transparency in money management led some opponents to call her "the Black Widow."

But the criticism rose to another level last month when Miller became the face of a lawsuit that legal experts call the most important constitutional case in a generation. Hers was among several lawsuits seeking Parliamentary input before Brexit, and judges made her the lead claimaint.

While Miller says she wants to protect the power of Parliament, Brexit supporters see the suit as an effort to circumvent the will of the people.

Prime Minister Theresa May says the June 23 vote gave her a mandate to take Britain out of the 28-nation bloc and that discussing her strategy with Parliament would weaken the government's position in exit negotiations.

May plans to invoke Article 50 of the EU treaty, the legal trigger that starts talks on Britain's exit, by the end of March using historic government powers known as royal prerogative. The powers are traditionally held by the monarch, but are now used by politicians to bypass a vote, enabling decisions as grave as declaring war or as basic as issuing passports.

Miller, who voted to remain part of the EU, argues that Parliament must have a vote because the rights of individuals in Britain are being revoked in the Brexit process. The freedom of movement across the EU, the freedom of trade in the bloc and the freedom to vote in European elections are among the rights that will change.

Feelings remain intense on both sides. Following the High Court's ruling last month, the Daily Mail newspaper featured photos of the judges under the headline "Enemies of the People." The Sun described those who filed the lawsuit as "a motley band of EU-based campaigners led by a foreign-born multi-millionaire."

The fury has surprised experts like Jeff King, professor of law at University College London.

"It has been common to criticize judges in the past, and I think criticism of judges is perfectly acceptable -- they are public officials after all," King said. "But this type of language, 'enemies of the people,' reminded me of the kinds of things we saw in Nazi Germany."

Few have come under as much criticism as Miller, who in many ways personifies the cosmopolitan, London-based elite that largely backed EU membership. Miller counters that her critics don't really know who she is.

From Guyana, Miller's family sent her to Britain to attend a girls-only boarding school. But political trouble back home meant that bank accounts were frozen and Miller found herself with no money.

Though underage, she found work as a chambermaid and scrubbed floors before and after school. She later worked as a model to pay for her education.

After earning a bachelor's degree in marketing and a law degree from the University of London, she decided against a legal career after she was advised that being a criminal barrister was not an appropriate job for a woman.

Instead, Miller found a job at German automaker BMW and went to work launching their U.K. fleet division, indulging her love of fast cars. In 1992, she started Sway Marketing to work with financial services firms.

"I have always been drawn to male-dominated industries and adrenaline-filled pursuits," she wrote in a short biography for "WeAretheCity," a networking organization.

Many British newspapers have focused on her personal life. She married young and has a disabled daughter, now in her late 20s, who still lives with her. She had two more children in her early 40s with her third husband, Alan Miller, an asset manager known in the tabloids as "Mr. Hedge Fund." Following the global financial crisis, Gina and Alan Miller founded SCMDirect, a small money management firm.

But it was her campaign for transparency in the fees that investment managers charge their clients that first won Miller widespread notice in business circles -- even as it made her unpopular among fellow asset managers.

Miller recalls attending an event at which she noticed a group of men staring at her. When she introduced herself, one of them told her she was known as "the black widow spider."

After an initial surge of anger, she paused.

"And then I thought: 'Well, thank you. That must mean I'm doing something right, because nobody in the city has managed to come up with an intellectual argument as to why it was wrong,"' Miller says.

"It's very much the same (with the Brexit lawsuit.) People do not talk about the case and the central pillars of our arguments of our case. They attack me personally, so I see it as they have nothing else to do. They are not attacking the message, they are attacking the messenger, which must mean I am winning."

Still, she says the vitriol is wearing on her. The threats and concern for her children make her wonder whether she'll be able to stay in Britain if the heat remains once the lawsuit is over. But there is no regret.

"I love Britain, and everything about Britain is about its inclusiveness, about its tolerance, about the great British way, " she said. "If that all disappears and we become this divisive, hateful, intolerant country, then every single one of us loses something. We lose part of our heart and we lose the heart of our country. And that's got to be something we all have to fight for."