London: Gina Miller has endured months of death threats and racist taunts for her decision to challenge the legal basis of Brexit, and while hopeful of victory on Tuesday, she is not looking forward to it.

“I think next week will be terrible,” she told AFP a few days before the Supreme Court rules on whether the government or parliament holds the power to start pulling Britain out of the European Union.

For many, the 51-year-old businesswoman has become a national hero for insisting MPs have the final say. For others, she is the “black widow spider” seeking to frustrate the result of last June’s referendum.

When she first brought the case, just days after the vote that split the country down the middle, Miller braced herself for criticism from Brexit supporters.

“I didn’t expect I would have to change my private life,” said the mother-of three.

The tabloid newspapers have dug into her past, she now has bodyguards, no longer takes public transport and keeps her family home at weekends.

Much of the hate mail has been racial, with some questioning whether Miller, born in what was then British Guiana and later became Guyana, was even British.

“Things that were considered unacceptable are now acceptable,” she said, admitting she is bracing for more abuse next week.

“I’ve even been told I’m a primate. I didn’t know we lived in that place. I think if I would have been a white man it would have been easier.”

Speaking in her private members’ club in central London, which has become a refuge when she is away from home, Miller insists she has no regrets.

She makes no secret of her opposition to Brexit — as an investment fund manager, she fears its economic impact — but says: “We lost the vote. We can’t undo that.”

The issue is about limits of executive power.

Prime Minister Theresa May believes she has the right to trigger Article 50 of the EU’s Lisbon Treaty, starting the formal departure process, without explicit approval from parliament.

In a ruling in November, the High Court disagreed, and the Supreme Court is widely expected to uphold this in its judgement on Tuesday.

“If we lose we will go back 400 years and I simply don’t believe the judges will do that,” Miller said.

“If a government is behaving this way it creates a precedent. Can you imagine? Any prime minister in the future could just decide with four or five ministers in a locked room.”

Without her legal bid, she believes Article 50 “would have been triggered last October with no plan, and illegally. That’s why I had to carry on.”

Six months after taking office, May finally set out her key objectives for the negotiations last week, promising to control immigration and pull Britain out of the EU’s single market.

“I think my case forced them to show their hand,” Miller said, but argued that parliament must now decide.

Miller grew up in a politically-active household — her father, Doodnaught Singh, was attorney general in Guyana — and previously launched a campaign to bring more transparency to financial investments.

She feels it is her duty to speak out when so many others are shouted down.

“Everything to do with Brexit is so emotional that everyone is afraid to stand up, and that’s a very bad place for us to be in,” she said.

Messages of support have also stiffened her resolve.

“I had a 10-year-old boy who drew me my own superhero emblem saying ‘Go Gina’. I have it on my desk,” she said.

“That gives me strength. Because I’m not invincible.”