Newly elected Conservative Party leader and British Prime Minister Boris Johnson speaks at 10 Downing Street in London, Britain, July 24, 2019. Newly-elected Conservative Party leader Boris Johnson took office as the British prime minister on Wednesday amid the rising uncertainties of Brexit. The latest development came after Theresa May formally stepped down as the leader of the country and Johnson was invited by the Queen to form the government. (Photo: Xinhua)

British Prime Minister Boris Johnson's political foes were jubilant on Tuesday after the country's top judges ruled that his five-week suspension of Parliament was unlawful.

With moves already being made to recall the House of Commons, politicians from across the spectrum were quick to condemn Johnson, with growing calls for him to resign as prime minister.

Opposition leader Jeremy Corbyn interrupted debate at the Labour Party conference in Brighton to announce the decision.

Cheered by delegates, Corbyn called for Johnson to "consider his position" as prime minister following the Supreme Court decision.

Corbyn said Johnson would become the shortest-serving prime minister there has ever been if he resigned.

He said Johnson should obey the law, take a no-deal Brexit off the table and call an election to elect a new government.

Labour's deputy leader Tom Watson also said Johnson should resign.

Prime Minister Johnson is currently in New York for the UN General Assembly.

Ian Blackford, leader of the Scottish National Party (SNP) at Westminster, joined the growing chorus, calling on Johnson to resign as prime minister.

Blackford, who leads the second largest opposition group after Labour in the House of Commons, said: "We must be back in Parliament immediately. We want to get back to work. On the back of this, Boris Johnson must resign."

Jo Swinson, leader of the minority Liberal Democratic Party, said the Supreme Court's decision confirmed that Johnson is not fit to be prime minister.

Former Conservative Attorney General Dominic Grieve said in a BBC interview that "I am not surprised with the judgement due to the gross misconduct by the prime minister...and I am delighted that the Supreme Court has stopped this unconstitutional act in its tracks."

Caroline Lucas, the Green Party's only MP at Westminster, said: "Parliament cannot be swept aside by prime ministerial whim. It must resume immediately."

The Speaker of the House of Commons, John Bercow, said he was consulting party leaders as a matter of urgency about recalling Parliament.

He said: "We must convene without delay. I welcome the Supreme Court's judgement that the prorogation of Parliament was unlawful."

"The judges have rejected the government's claim that closing down Parliament for five weeks was merely standard practice to allow for a new Queen's Speech", he said.