A display of U.K., Union Jack flags fly in front of The Houses of Parliament, in London, U.K., on Monday, Feb. 15, 2016. Jason Alden | Bloomberg | Getty Images

The U.K. Supreme Court's ruling that parliament must vote on whether the British government can start the Brexit process marks the start of a tumultuous period of legal disputes for U.K. Prime Minister Theresa May.

The Supreme Court ruled against the government with a majority of eight to three on Tuesday in a landmark case with potentially significant political ramifications.







Cliff-edge Brexit deal

Downing Street confirmed on Tuesday that May's pledge to trigger Article 50 of the European Union's (EU) Lisbon Treaty, the formal step required to begin the process of exiting the bloc, before the end of March would not be impacted by the Supreme Court ruling. The U.K. Prime Minister announced last week that parliament would get a say on the final Brexit deal too. This means that the Supreme Court ruling on Tuesday effectively bookends the U.K.'s Brexit negotiations with votes in parliament. "There is a serious question of how valid a (final Brexit deal vote in parliament) would be. Unfortunately for the U.K., the two-year deadline and Article 50 process is designed to give the much bigger EU more leverage than the exiting country," Kallum Pickering, senior U.K. economist at Berenberg Bank told CNBC in an email. "Once the U.K. triggers Article 50, likely in March, the two-year countdown begins. If the U.K. doesn't agree to the terms of the post-Brexit deal and likely transitional arrangements then it may suffer a cliff-edge Brexit and find itself trading with the EU on World Trade Organization terms. That would be the worst outcome for the economy," he added.

More legal hurdles to clear