Britain is already steeped in a state of deep uncertainty about how exactly it will handle its exit from the European Union—and a Brexit-related lawsuit, whose lead claimant is investment manager Gina Miller, threatens to make things even more complex.

Miller is challenging the U.K. government’s belief that it alone can trigger Article 50 to launch Britain out of the EU. She argues that the break-up must be done by parliamentary vote. The High Court started hearing her case this week, but the backlash against her side began much earlier. Demonstrators appeared outside the law firm representing her and an attorney working on the case told the Guardian there have been “a number of death threats.”

Miller is used to facing intense criticism. She’s the co-founder of SCM Private LLC, but is also a vocal advocate for asset managers to disclose exactly how much they charge investors—a position that has made her an unpopular figure in the industry. In an interview with the FT in April, she recalled attendees at an industry party referring to her as a “disgrace” whose lobbying would “bring down the entire City.”

“I believe that level of abuse means I am doing something right for investors,” she said.

Whether Miller gets that same kind of redemption in the Brexit case is now a matter for the courts to decide.