"The legislation is intended to ensure we don't leave without a deal, that will require an extension," Starmer told the BBC.
Earlier on Sunday, Michel Barnier, the EU's lead Brexit negotiator, refused UK Prime Minister Boris Johnson’s demand to scrap the Irish backstop, increasing chances for the latter to proceed with a no-deal withdrawal.
On Wednesday, Queen Elizabeth approved Boris Johnson's plan to prorogue the parliament in mid-September until 14 October, when Her Majesty will also outline the government's post-Brexit agenda.
The United Kingdom voted to leave the European Union in 2016. After former Prime Minister Theresa May failed to come up with an acceptable plan to leave the bloc by 29 March of this year, the deadline was moved to 31 October.
Prime Minister Boris Johnson has repeatedly stated his determination to withdraw the United Kingdom from the bloc by the October 31 deadline, with or without a deal, despite there being strong objections to no-deal among parliamentarians.