John Bercow has announced MPs will return to the Commons on Wednesday at 11.30am, after the Supreme Court ruled Boris Johnson’s decision to suspend parliament for five weeks was unlawful.

“The citizens of the UK are entitled to expect parliament does discharge its core functions, that it is in a position to scrutinise the executive, to hold ministers to account and to legislate if it chooses,” he told TV cameras outside parliament on Tuesday afternoon.

Jeremy Corbyn has demanded the prime minister resign following the bombshell ruling, as he prepared to return to London from the Labour conference in Brighton.

“I invite Boris Johnson in the historic words to consider his position and become the shortest-serving prime minister there’s ever been,” he told party members to loud cheers.

The Labour leader has brought forward to this afternoon his keynote conference speech which has been due to be delivered tomorrow.

The prime minister is currently in New York attending the UN general assembly and has yet to comment on the ruling.

A panel of 11 justices at the court in London ruled unanimously that the PM’s advice to the Queen to suspend parliament until October 14 was unlawful because it had the effect of frustrating parliament.

The court also held that the prorogation itself was “void and of no effect” and therefore parliament has not been suspended.

Nicola Sturgeon, the SNP leader and Scottish first minister, has also demanded Johnson quit as PM. Lib Dem leader Jo Swinson said Johnson was “not fit” to be in Downing Street.