The top lawyer opposing the Government's Brexit appeal is due to continue his case at the Supreme Court.
Lord Pannick QC appears for Gina Miller, the investment fund manager and philanthropist who won a historic ruling against the Government at the High Court last month.
On November 3, three judges in London decided that Prime Minister Theresa May lacked power to use the royal prerogative to trigger Article 50 of the Lisbon Treaty and start the two-year process of negotiating Brexit without the prior authority of Parliament.
Lord Pannick will continue to present his case before a panel of 11 Supreme Court justices on the third day of the Government's challenge against the High Court's ruling.
Members of the public queued early once again on Wednesday to gain a place in court to witness the landmark proceedings.
On Tuesday, James Eadie QC, for the Government, insisted that it does have the legal power to use the prerogative to trigger Britain's exit from the European Union following the June 23 referendum which resulted in a leave vote.
But Lord Pannick countered that no such power exists. He declared: "Parliament is sovereign. What Parliament created, only Parliament can take away."
Mr Eadie rejected the suggestion that the Government's Brexit strategy was an "affront" to parliamentary sovereignty.
Mrs May has made it clear she still intends to give an Article 50 notification by the end of next March to start the leave negotiations with 27 other EU countries. The case is due to finish on Thursday with a ruling in the new year.