Former British prime minister David Cameron, who took the decision in 2016 to hold a referendum on the country’s membership in the European Union, said another vote may be needed to resolve the Brexit impasse.

In an interview with the Times published on Friday ahead of the launch of his memoirs, entitled For the Record, Cameron said a no-deal Brexit would be “a bad outcome,” which should not be pursued and said a second referendum remained an option.

“I don’t think you can rule it out because we’re stuck,” said Cameron, who served as Conservative prime minister from 2010 to 2016 and campaigned in the referendum for Britain to remain in the EU.

“I’m not saying one will happen or should happen. I’m just saying that you can’t rule things out right now because you’ve got to find some way of unblocking the blockage,” said Cameron, in his first interview since he resigned the day after Brits voted in the referendum by 52 per cent to 48 per cent to leave the EU.

Britain has been mired ever since in complex divorce talks with the EU. The country, first under Theresa May and since July under Boris Johnson, who was one of the leading campaigners for Leave in the 2016 vote, remains deeply divided on the issue.

Cameron said he worried “desperately” about what is going to happen next, but defended holding the referendum in 2016 as necessary to achieve a renegotiation of Britain’s relationship with the EU.

Watch: Johnson says he will not request Brexit extension

U.K. Prime Minister Boris Johnson said on Tuesday he would not request an extension to Brexit, hours after a law came into force demanding that he delay Britain’s departure from the European Union until 2020 unless he can strike a divorce deal. Meanwhile, House of Commons Speaker John Bercow says he will stand down. 3:20

Johnson says Britain must now leave the EU on Oct. 31 whether or not he reaches an exit deal. But Parliament passed a law last week over his objections ordering him to seek an extension if he fails to reach an agreement with the bloc.

Johnson said Friday there was “the rough shape of a deal to be done” over Brexit, but Irish Prime Minister Leo Varadkar played down the prospects, saying the gap between Britain and the EU remained “very wide.”

In his interview, Cameron was critical of Johnson’s decision to expel 21 Conservative lawmakers from the party for voting against the government, as well as his move to shut down, or prorogue, Parliament until mid-October. The decision to suspend Parliament is now being challenged in the British courts.

“I didn’t support either of those things,” Cameron said.

He also said Johnson and Michael Gove, currently the minister in charge of no-deal Brexit planning, and who was also a prominent Leave supporter in the referendum, had “left the truth at home” during the campaign.

Speaker calls on Johnson to respect law

The Speaker of Britain’s lower house of Parliament has made it abundantly clear he is not going quietly into retirement at the end of October.

House of Commons Speaker John Bercow used a speech Thursday night to warn Johnson to expect Parliament to take aggressive action to make sure its legislation designed to block a no-deal Brexit is respected.

He says he will allow “procedural creativity” in making sure Johnson doesn’t violate the new law, which took effect this week.

Speaker of the House of Commons John Bercow used a speech Thursday night to warn Johnson to expect Parliament to take aggressive action to make sure its legislation designed to block a no-deal Brexit is respected. (UK Parliament/Jessica Taylor/via Reuters)

It requires Johnson to ask the EU for an extension of the Oct. 31 Brexit deadline if no deal is reached by mid-October.

Johnson has said he will not seek an extension under any circumstances, saying colourfully he would rather be “dead in a ditch” than delay Brexit again.

Bercow said the prime minister must obey the law and that it is “astonishing” any other course is being contemplated.

“It would be the most terrible example to set to the rest of society,” he said.

Bercow plans to step down from his influential post by the end of October, but it is clear he will use his final weeks in office to make sure Parliament’s will is respected on the crucial question of a possible no-deal departure from the EU bloc.

The government’s own assessment suggests an abrupt departure without an agreement risks severe economic problems and possible food and medicine shortages in Britain.

Listen: ‘Be a good boy’ and other moments from Bercow’s speakership

British MPs have a tough job ahead of them: figuring out what to do with Brexit. John Bercow might have a more challenging task. As Speaker of the House of Commons, he’s the one trying to keep order. 3:22

Parliament is currently suspended for five weeks, but Johnson’s decision to suspend the legislative branch for such an extended period has been ruled unlawful by a Scottish court and will be taken up by the U.K. Supreme Court on Tuesday.

An adverse decision for Johnson at Britain’s highest court would bring the feisty Parliament back into session earlier than he had intended.

It would also raise questions about whether Johnson’s government misled Queen Elizabeth when it requested her approval for a five-week suspension.

Watch: Secret U.K. document describes worst case for Brexit