Opposition Labour Party leader Jeremy Corbyn called on Prime Minister Boris Johnson on Tuesday to resign, but said he would not press for a new election until he was sure Britain would not leave the European Union without a deal.

Corbyn said he would do all he could to ensure that Johnson takes a so-called no-deal Brexit "off the table," setting up an uncomfortable showdown for the prime minister, who insisted he would still oversee Britain's departure on Oct. 31.

A Supreme Court ruling that Johnson's move to suspend Parliament was unlawful has set up a standoff on Wednesday, when lawmakers will return to Westminster and try to force the prime minister to reveal his plans and rule out a no-deal Brexit.