Brexit News: Why Was Boris Johnson's Move To Suspend UK Parliament Deemed Unlawful?

The U.K.'s highest court ruled Tuesday that Prime Minister Boris Johnson's move to suspend Parliament this month was unlawful. Johnson had suspended Parliament from Sept. 11 to Oct. 14, which means Parliament is now in session and can continue the Brexit debate.

The British Supreme Court's president, Lady Hale, said that "the decision to advise Her Majesty to prorogue parliament was unlawful because it had the effect of frustrating or preventing the ability of Parliament to carry out its constitutional functions without reasonable justification."

The decision came after a three-day appeal hearing. All 11 Supreme Court judges were in favor of the ruling.

Parliament could reconvene as early as 11:30 a.m. BST on Wednesday.

The ruling is considered unprecedented, as judges have been thrust into a political debate about Brexit.

"I strongly disagree with the judgment, and we in the U.K. will not be deterred from getting and delivering on the will of the people to come out of the EU on Oct. 31," Johnson said, who is in New York for the United Nations General Assembly. He has not ruled out suspending Parliament again.

The official legal term to suspend parliament is prorogation, a formal mechanism that dates back to the 15th century.

Typically, the prime minister can ask the Queen to prorogue parliament for several weeks before the event. In this case, the Queen had granted Johnson a five-week prorogation before her Oct. 14 address. Queen Elizabeth will give the Queen's Speech, an annual address where she outlines parliamentary priorities for the coming year.

Johnson had asked for a prorogation not just for tradition's sake, but critics believe it was for his own political goals.

He had pledged that the U.K. would leave the EU, with or without a deal, by Oct. 31. By asking for a prorogation of parliament, Johnson could bide his time until the Oct. 31 Brexit date, with Parliament unable to convene or pass legislation and having little opportunity to prevent Brexit from happening at the end of October.

Since the Supreme Court has shot down the prorogation, Parliament is likely to reconvene on Wednesday, with many officials expected to lambast Johnson's Brexit strategy. The leader of the Labour Party and of the Opposition, Jeremy Corbyn, has called on Johnson to resign.

"So, obey the law, take 'no deal' off the table, and have an election for a government that respects democracy and brings power back to the people, not usurps it in the way that Boris Johnson has done," Corbyn said Tuesday after the ruling.

Johnson will address the U.N. General Assembly on Tuesday before returning to London overnight.