Miller, the lead claimant in a Brexit lawsuit, proved victorious when Britain’s High Court ruled in her favor on how the country must proceed with its bid to leave the diplomatic bloc. The ruling said parliament must vote to trigger Article 50 of the EU’s treaty, which allows member states to leave the union. The government had argued that the nationwide balloting on June 23, which resulted in a vote to leave the EU, and its own executive power were enough for it to notify Brussels without parliament’s consent. It is appealing the court’s decision.

The ruling was a major strike against May since she has laid out a Brexit timetable that doesn’t necessarily allow for a parliamentary vote. She had said that Brexit talks would start before the end of March. While analysis of the ruling says that timing is now up in the air, a spokeswoman for May disagreed, telling reporters, “Our plan remains to invoke Article 50 by the end of March, we believe the legal timetable should allow for that.” Britain’s Supreme Court is expected to hear the appeal in early December.

Subscribe to The World’s Most Powerful Women, Fortune’s daily must-read for global businesswomen.

The ruling infused even more derision into an already-tense climate. The divisive June vote split the country by many dimensions—young versus old, rich versus poor, urban versus rural—and exposed waves of anti-immigrant sentiment.

Some Twitter users saluted Miller for her “bravery” in bringing the case, while others made racist comments about Miller—she was born in Guyana—and accused her of treason.

After the decision was announced, Miller spoke to reporters outside the Royal Courts of Justice, and said her lawsuit was about Britain as a whole, not her personally. “This case was about process not politics,” said Miller, co-founder of investment boutique SCM Private who opposed Brexit. “My dedicated team are absolutely delighted to be able to be part of this debate and to bring some sobriety as we go forward.”

In the run-up to Thursday’s ruling, Miller explained her reasons for challenging the government, telling Business Insider UK in August that people in Britain “must not underestimate or forget the anger in Europe about our vote.” She added that the U.K. “has always had a special relationship with the EU. They’ve given to us significantly over the years and we’ve always had a veto.”

But Miller’s remarks have done little to stave off backlash. In October, near the offices of Mishcon de Reya—the law firm representing Miller, et al.—protesters appeared with signs saying, “Invoke Article 50 now” and “Uphold the Brexit vote.” Those leading the legal challenge have received much more serious criticism, including death threats and online abuse. At one preliminary hearing for the case, a judge ordered the identities of some plaintiffs withheld for their own protection.

This isn’t the first time Miller has been in the middle of a controversy. She’s gained a reputation as an advocate against hidden fund charges and has decried what she characterizes as flagrant mis-selling of funds. Miller launched investment boutique SCM Private with her husband in 2009 after the financial crisis showed her how opaque the asset management industry was. Her firm is built on low-cost passive investment strategies, but also actively manages how the assets are allocated.

She’s pushed asset managers to disclose exactly how much they charge investors. That activism, she told the Financial Times in April, has sapped her popularity in the profession. At one industry party, three attendees called her a disgrace. “One of them replied…that my lobbying efforts would bring down the entire City [of London],” she said, referring to London’s financial district. “I believe that level of abuse means I am doing something right for investors.”

She took that same approach in facing flack for the Brexit case. Boycotts of her business and Facebook campaigns “encouraging people to do things to me,” haven’t deterred her, she said. “That fuels me more. We cannot let bullies hijack this process. It certainly isn’t a comfortable place to be.”