Gina Miller will give up her Brexit battle if Britain's government wins the Article 50 court case appeal
Miller, an investment manager based in London, spearheaded a legal challenge that led three High Court Judges to rule last month that May must pass an act of parliament before initiating Britain's exit from the European Union.
The government argued that it has the right to bypass parliament and use royal prerogative to trigger Article 50. It decided to appeal the High Court's decision, meaning the case will be revisited by the Supreme Court next month.
Speaking to Bloomberg, Miller, who Business Insider interviewed in August prior to the High Court case, said she has no intention of taking the case to the European Courts if the government is successful in its appeal.
"My particular case is a constitutional one in Britain so I would not be going [to the European Courts]... whatever the outcome" she said.
"That's not to say the Supreme Court itself won't say that aspects of Article 50 need to be debated at an international level."
The High Court's unanimous ruling triggered a political earthquake in Britain. Numerous pro-Brexit MPs accused the judges, who are among the country's most qualified, of trying to reverse the referendum result, while a host of right-wing newspapers published explosive front pages the following day. The Mail, for example, described the judges as "enemies of the people" while the Express said the verdict was as "grave" as World War 2.
Miller's legal representatives argued successfully that triggering Article 50 would result in rights enjoyed by Brits as EU citizens - like the right to vote to in EU elections and refer a legal dispute to the European Court of Justice - will be destroyed in an instant, without MPs having a say.
If the Supreme Court upholds the High Court's verdict, it means May will be required to pass an act of parliament before triggering Article 50 - the legal mechanism reserved for countries looking to leave the EU.
The prime minister shouldn't experience any difficulty securing parliamentary approval, with most MPs keen to respect the public will, however, a handful MPs from across the house have threatened to block the bill if they are not satisfied with May's negotiation position, including all eight Liberal Democrat MPs and almost every SNP representative.
Labour's shadow Brexit minister Keir Starmer has said the party will not block Article 50 but will demand May disclose more details about the government's negotiation strategy before initiating Britain's formal departure.