The Supreme Court of the United Kingdom ruled Tuesday the suspension, or proroguing, of the British Parliament by prime minister Boris Johnson was unlawful and, therefore, void.

It was a stunning defeat for Johnson, who will now have to deal with Parliament from a position of inferiority and with his authority in shambles by his own hand. Calls for Johnson's removal from office are mounting among Members of Parliament (MPs) and the public. Johnson stands to become the shortest-serving prime minister in British history.

The unanimous decision by all 11 justices of the court also meant Johnson had lied to Queen Elizabeth II about his reason for proroguing Parliament. Parliament was suspended from Sept. 10 to Oct. 14 due to Johnson's proroguing.

The Supreme Court squashed Johnson's suspension in its entirety. The justices also ruled it was for Parliament to decide what to do next. The ruling means Parliament was never prorogued and MPs can return to work tomorrow and again begin deliberations on Brexit.

Speaking for the court, the President of the Supreme Court, Lady Brenda Hale, said the suspension of Parliament was not a normal suspension and had taken place in exceptional circumstances. She said there was no justification for Johnson taking such an extreme measure as suspending Parliament for five weeks.

"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," said Lady Hale.

The Supreme Court also said it was wrong to stop MPs carrying out duties in the run-up to Brexit, which takes effect on Oct. 31. Lady Hale said, "the effect on the fundamentals of democracy was extreme."

Opposition lawmakers said the government's aim in proroguing Parliament was to frustrate parliamentary debate on Brexit. Johnson's government denied this, claiming the shutdown was normal procedure. It also said it will allow Parliament to return in October and introduce new plans for the next parliamentary year.

Johnson, who is currently at the United Nations General Assembly, hasn't been reached for his comments on the Supreme Court decision. His allies, however, said they're "currently processing the verdict."