Jeremy Corbyn has said Boris Johnson should “consider his position” as prime minister, after the Supreme Court ruled his decision to suspend parliament for five weeks was unlawful.

Speaking in Brighton at Labour’s conference shortly after the bombshell decision in London, Corbyn said Johnson should become “the shortest serving prime minister there has ever been”.

To cheers and applause from party members, the Labour leader said the PM had shown a “contempt for democracy and an abuse of power”.

Corbyn said he was demanding parliament be recalled so Labour could question the government. 

“Our parliament is elected by our people to hold our government to account,” he said.

“I invite Boris Johnson, in the historic words, to consider his position and become the shortest serving prime minister there has ever been,” he added.

The Labour leader’s comments indicate he will cancel or move the speech he had planned to deliver to the conference tomorrow afternoon.

John Bercow, the Commons Speaker, said parliament must now “convene without delay”.

“I will now consult the party leaders as a matter of urgency,” he said in a statement.

Ian Backford, the SNP’s leader in Westminster, has also said Johnson should resign.

And Lib Dem leader Jo Swinson said Johnson “isn’t fit” to be prime minister. “He’s misled Queen and country, and unlawfully silenced the people’s representatives,” she tweeted.

A panel of 11 justices at the Supreme Court in London gave their decision on Tuesday in a ruling on the legality of the prime minister’s advice to the Queen to prorogue Parliament until October 14.

The judges, led by the court’s president Lady Hale, heard appeals over three days arising out of legal challenges in England and Scotland – which produced different outcomes.

The panel held unanimously that Johnson’s advice to the Queen was unlawful because it had the effect of frustrating parliament.

The court also found the prorogation and was also “void and of no effect” – meaning parliament has not been suspended.