Boris Johnson could be forced to request a delay to Brexit as early as next week, after opposition parties began discussions on a new plan to block a no-deal departure from the EU.

The prime minister has vowed to take the UK out of the EU on 31 October with or without a deal.

But the so-called Benn Act, pushed through parliament by the ‘rebel alliance’ earlier this month, requires him to seek an extension to the Article 50 negotiation process by 19 October unless he manages to secure parliamentary support by that date for a withdrawal agreement or a no-deal outcome.

Liberal Democrat sources confirmed that they are now working with other opposition parties to bring the deadline forward, though agreement has not yet been reached on a new date.

Although the change would require fresh legislation, it is understood that this could be forced thro​ugh a parliament where the Conservatives no longer have a majority in time to force Mr Johnson to go to Brussels as early as next week.

Thousands protest after Boris Johnson requests to suspend parliament Show all 29 1 /29 Thousands protest after Boris Johnson requests to suspend parliament Thousands protest after Boris Johnson requests to suspend parliament Houses of Parliament An anti-Brexit supporter raises a sign during a protest in front of the Houses of Parliament in central London, Wednesday, Aug. 28, 2019. British Prime Minister Boris Johnson maneuvered on Wednesday to give his political opponents even less time to block a no-deal Brexit before the Oct. 31 withdrawal deadline, winning Queen Elizabeth II's approval to suspend Parliament. (AP Photo/Vudi Xhymshiti) Vudi Xhymshiti AP Thousands protest after Boris Johnson requests to suspend parliament Downing Street Anti-Brexit demonstrators hold placards as they protest outside of Downing Street in London on August 28, 2019. - British Prime Minister Boris Johnson sparked fury Wednesday among pro-Europeans and MPs opposed to a no-deal Brexit by forcing the suspension of parliament weeks before Britain's EU departure date. The pound slid on the surprise news, which opponents branded a "coup" and a "declaration of war" but Johnson claimed was necessary to allow him to pursue a "bold and ambitious" new domestic legislative agenda. (Photo by DANIEL SORABJI / AFP)DANIEL SORABJI/AFP/Getty Images DANIEL SORABJI AFP/Getty Images Thousands protest after Boris Johnson requests to suspend parliament Houses of Parliament Anti-Brexit supporters take part in a protest in front of the Houses of Parliament in central London, Wednesday, Aug. 28, 2019. British Prime Minister Boris Johnson maneuvered on Wednesday to give his political opponents even less time to block a no-deal Brexit before the Oct. 31 withdrawal deadline, winning Queen Elizabeth II's approval to suspend Parliament. (AP Photo/Vudi Xhymshiti) Vudi Xhymshiti AP Thousands protest after Boris Johnson requests to suspend parliament Houses of Parliament to Downing Street TOPSHOT - Anti-Brexit demonstrators hold placards as they take part in a protest march from Britain's Houses of Parliament to Downing Street in London on August 28, 2019. - British Prime Minister Boris Johnson announced Wednesday that the suspension of parliament would be extended until October 14 -- just two weeks before the UK is set to leave the EU -- enraging anti-Brexit MPs. MPs will return to London later than in recent years, giving pro-EU lawmakers less time than expected to thwart Johnson's Brexit plans before Britain is due to leave the European Union on October 31. (Photo by DANIEL SORABJI / AFP)DANIEL SORABJI/AFP/Getty Images DANIEL SORABJI AFP/Getty Images Thousands protest after Boris Johnson requests to suspend parliament Downing Street Anti-Brexit supporters gather outside the Prime Minister's residence 10 Downing Street in London, Wednesday, Aug. 28, 2019. British Prime Minister Boris Johnson asked Queen Elizabeth II on Wednesday to suspend Parliament, throwing down the gauntlet to his critics and causing outrage among opposition leaders who will have even less time to thwart a no-deal Brexit. (AP Photo/Matt Dunham) Matt Dunham AP Thousands protest after Boris Johnson requests to suspend parliament Houses of Parliament LONDON, ENGLAND - AUGUST 28: Pro-EU supporters protest outside the Houses of Parliament on August 28, 2019 in London, England. British Prime Minister Boris Johnson has written to Cabinet colleagues telling them that his government has requested the Queen suspend parliament for longer than the usual conference season. Parliament will return for a new session with a Queen's Speech on 14 October 2019. Some Remain supporting MPs believe this move to be a ploy to hinder legislation preventing a No Deal Brexit. (Photo by Peter Summers/Getty Images) Peter Summers Getty Images Thousands protest after Boris Johnson requests to suspend parliament Houses of Parliament epa07799808 A protestor outside the Houses of Parliament in Westminster, London, Britain, 28 August 2019. The UK government is to suspend Parliament after the summer break, a move that might block MPs from voting against a possible no-deal Brexit.. EPA/WILL OLIVER WILL OLIVER EPA Thousands protest after Boris Johnson requests to suspend parliament Houses of Parliament Anti-Brexit supporters take part in a protest near the Houses of Parliament in central London, Wednesday, Aug. 28, 2019. British Prime Minister Boris Johnson asked Queen Elizabeth II on Wednesday to suspend Parliament, throwing down the gauntlet to his critics and causing outrage among opposition leaders who will have even less time to thwart a no-deal Brexit. (AP Photo/Matt Dunham) Matt Dunham AP Thousands protest after Boris Johnson requests to suspend parliament Whitehall TOPSHOT - Demonstrators hold placards as they protest on Whitehall, near the entrance to Downing Street in London on August 28, 2019. - British Prime Minister Boris Johnson sparked fury Wednesday among pro-Europeans and MPs opposed to a no-deal Brexit by forcing the suspension of parliament weeks before Britain's EU departure date. The pound slid on the surprise news, which opponents branded a "coup" and a "declaration of war" but Johnson claimed was necessary to allow him to pursue a "bold and ambitious" new domestic legislative agenda. (Photo by DANIEL SORABJI / AFP)DANIEL SORABJI/AFP/Getty Images DANIEL SORABJI AFP/Getty Images Thousands protest after Boris Johnson requests to suspend parliament Houses of Parliament Anti-Brexit supporters take part in a protest at College Green near the Houses of Parliament in central London, Wednesday, Aug. 28, 2019. British Prime Minister Boris Johnson maneuvered Wednesday to give his political opponents even less time to block a no-deal Brexit before the Oct. 31 withdrawal deadline, winning Queen Elizabeth II's approval to suspend Parliament. (AP Photo/Matt Dunham) Matt Dunham AP Thousands protest after Boris Johnson requests to suspend parliament Anti-Brexit supporters take part in a protest at College Green near the Houses of Parliament in central London, Wednesday, Aug. 28, 2019. British Prime Minister Boris Johnson maneuvered Wednesday to give his political opponents even less time to block a no-deal Brexit before the Oct. 31 withdrawal deadline, winning Queen Elizabeth II's approval to suspend Parliament. (AP Photo/Matt Dunham) Matt Dunham AP Thousands protest after Boris Johnson requests to suspend parliament Protestors from the European Movement in Scotland hold a walking vigil on the Royal Mile, Edinburgh, to demonstrate against Prime Minister Boris Johnson temporarily closing down the Commons from the second week of September until October 14 when there will be a Queen's Speech to open a new session of Parliament. PRESS ASSOCIATION Photo. Picture date: Wednesday August 28, 2019. See PA story POLITICS Brexit. Photo credit should read: Jane Barlow/PA Wire Jane Barlow PA Thousands protest after Boris Johnson requests to suspend parliament Anti-Brexit supporters shout slogans as they gather outside the Prime Minister's residence 10 Downing Street in London, Wednesday, Aug. 28, 2019. British Prime Minister Boris Johnson asked Queen Elizabeth II on Wednesday to suspend Parliament, throwing down the gauntlet to his critics and causing outrage among opposition leaders who will have even less time to thwart a no-deal Brexit. (AP Photo/Matt Dunham) Matt Dunham AP Thousands protest after Boris Johnson requests to suspend parliament Anti-Brexit supporters take part in a protest at College Green near the Houses of Parliament in central London, Wednesday, Aug. 28, 2019. British Prime Minister Boris Johnson maneuvered Wednesday to give his political opponents even less time to block a no-deal Brexit before the Oct. 31 withdrawal deadline, winning Queen Elizabeth II's approval to suspend Parliament. (AP Photo/Matt Dunham) Matt Dunham AP Thousands protest after Boris Johnson requests to suspend parliament Anti-Brexit supporters take part in a protest at College Green near the Houses of Parliament in central London, Wednesday, Aug. 28, 2019. British Prime Minister Boris Johnson maneuvered Wednesday to give his political opponents even less time to block a no-deal Brexit before the Oct. 31 withdrawal deadline, winning Queen Elizabeth II's approval to suspend Parliament. (AP Photo/Matt Dunham) Matt Dunham AP Thousands protest after Boris Johnson requests to suspend parliament Anti-Brexit supporters gather outside the Prime Minister's residence 10 Downing Street in London, Wednesday, Aug. 28, 2019. British Prime Minister Boris Johnson asked Queen Elizabeth II on Wednesday to suspend Parliament, throwing down the gauntlet to his critics and causing outrage among opposition leaders who will have even less time to thwart a no-deal Brexit. (AP Photo/Matt Dunham) Matt Dunham AP Thousands protest after Boris Johnson requests to suspend parliament Anti-Brexit supporters take part in a protest at College Green near the Houses of Parliament in central London, Wednesday, Aug. 28, 2019. British Prime Minister Boris Johnson maneuvered Wednesday to give his political opponents even less time to block a no-deal Brexit before the Oct. 31 withdrawal deadline, winning Queen Elizabeth II's approval to suspend Parliament. (AP Photo/Matt Dunham) Matt Dunham AP Thousands protest after Boris Johnson requests to suspend parliament Shadow home secretary Diane Abbott addresses protesters outside the Houses of Parliament, London, to demonstrate against Prime Minister Boris Johnson temporarily closing down the Commons from the second week of September until October 14 when there will be a Queen's Speech to open a new session of Parliament. PRESS ASSOCIATION Photo. Picture date: Wednesday August 28, 2019. See PA story POLITICS Brexit. Photo credit should read: Kirsty O'Connor/PA Wire Kirsty O'Connor PA Thousands protest after Boris Johnson requests to suspend parliament epa07799846 Protesters gather outside the Houses of Parliament in Westminster, London, Britain, 28 August 2019. The UK government is to suspend Parliament after the summer break, a move that might block MPs from voting against a possible no-deal Brexit. EPA/WILL OLIVER WILL OLIVER EPA Thousands protest after Boris Johnson requests to suspend parliament Anti-Brexit supporters gather outside the Prime Minister's residence 10 Downing Street in London, Wednesday, Aug. 28, 2019. British Prime Minister Boris Johnson asked Queen Elizabeth II on Wednesday to suspend Parliament, throwing down the gauntlet to his critics and causing outrage among opposition leaders who will have even less time to thwart a no-deal Brexit. (AP Photo/Matt Dunham) Matt Dunham AP Thousands protest after Boris Johnson requests to suspend parliament Anti-Brexit supporters carry a flare near the Cenotaph in central London, Wednesday, Aug. 28, 2019. British Prime Minister Boris Johnson asked Queen Elizabeth II on Wednesday to suspend Parliament, throwing down the gauntlet to his critics and causing outrage among opposition leaders who will have even less time to thwart a no-deal Brexit. (AP Photo/Matt Dunham) Matt Dunham AP Thousands protest after Boris Johnson requests to suspend parliament Anti-Brexit demonstrators hold placards as they protest outside of Downing Street in London on August 28, 2019. - British Prime Minister Boris Johnson sparked fury Wednesday among pro-Europeans and MPs opposed to a no-deal Brexit by forcing the suspension of parliament weeks before Britain's EU departure date. The pound slid on the surprise news, which opponents branded a "coup" and a "declaration of war" but Johnson claimed was necessary to allow him to pursue a "bold and ambitious" new domestic legislative agenda. (Photo by DANIEL SORABJI / AFP)DANIEL SORABJI/AFP/Getty Images DANIEL SORABJI AFP/Getty Images Thousands protest after Boris Johnson requests to suspend parliament Anti-Brexit demonstrators hold placards as they protest outside of Downing Street in London on August 28, 2019. - British Prime Minister Boris Johnson sparked fury Wednesday among pro-Europeans and MPs opposed to a no-deal Brexit by forcing the suspension of parliament weeks before Britain's EU departure date. The pound slid on the surprise news, which opponents branded a "coup" and a "declaration of war" but Johnson claimed was necessary to allow him to pursue a "bold and ambitious" new domestic legislative agenda. (Photo by DANIEL SORABJI / AFP)DANIEL SORABJI/AFP/Getty Images DANIEL SORABJI AFP/Getty Images Thousands protest after Boris Johnson requests to suspend parliament LONDON, ENGLAND - AUGUST 28: Pro-EU supporters protest outside the Houses of Parliament on August 28, 2019 in London, England. British Prime Minister Boris Johnson has written to Cabinet colleagues telling them that his government has requested the Queen suspend parliament for longer than the usual conference season. Parliament will return for a new session with a Queen's Speech on 14 October 2019. Some Remain supporting MPs believe this move to be a ploy to hinder legislation preventing a No Deal Brexit. (Photo by Peter Summers/Getty Images)(Photo by Peter Summers/Getty Images) Peter Summers Getty Images Thousands protest after Boris Johnson requests to suspend parliament Anti-Brexit supporters continue to participate in a late evening protest in front of the Houses of Parliament in central London, Wednesday, Aug. 28, 2019. British Prime Minister Boris Johnson maneuvered on Wednesday to give his political opponents even less time to block a no-deal Brexit before the Oct. 31 withdrawal deadline, winning Queen Elizabeth II's approval to suspend Parliament. (AP Photo/Vudi Xhymshiti) Vudi Xhymshiti AP Thousands protest after Boris Johnson requests to suspend parliament London metropolitan police talk with anti-Brexit supporters in front of the Houses of Parliament in central London, Wednesday, Aug. 28, 2019. British Prime Minister Boris Johnson maneuvered on Wednesday to give his political opponents even less time to block a no-deal Brexit before the Oct. 31 withdrawal deadline, winning Queen Elizabeth II's approval to suspend Parliament. (AP Photo/Vudi Xhymshiti) Vudi Xhymshiti AP Thousands protest after Boris Johnson requests to suspend parliament LONDON, ENGLAND - AUGUST 28: A Pro-EU supporter raises her fist during a protest outside the Houses of Parliament on August 28, 2019 in London, England. British Prime Minister Boris Johnson has written to Cabinet colleagues telling them that his government has requested the Queen suspend parliament for longer than the usual conference season. Parliament will return for a new session with a Queen's Speech on 14 October 2019. Some Remain supporting MPs believe this move to be a ploy to hinder legislation preventing a No Deal Brexit. (Photo by Peter Summers/Getty Images) Peter Summers Getty Images Thousands protest after Boris Johnson requests to suspend parliament LONDON, ENGLAND - AUGUST 28: Pro-EU supporters protest outside the Houses of Parliament on August 28, 2019 in London, England. British Prime Minister Boris Johnson has written to Cabinet colleagues telling them that his government has requested the Queen suspend parliament for longer than the usual conference season. Parliament will return for a new session with a Queen's Speech on 14 October 2019. Some Remain supporting MPs believe this move to be a ploy to hinder legislation preventing a No Deal Brexit. (Photo by Peter Summers/Getty Images)(Photo by Peter Summers/Getty Images) Peter Summers Getty Images Thousands protest after Boris Johnson requests to suspend parliament LONDON, ENGLAND - AUGUST 28: Pro-EU supporters protest outside the Houses of Parliament on August 28, 2019 in London, England. British Prime Minister Boris Johnson has written to Cabinet colleagues telling them that his government has requested the Queen suspend parliament for longer than the usual conference season. Parliament will return for a new session with a Queen's Speech on 14 October 2019. Some Remain supporting MPs believe this move to be a ploy to hinder legislation preventing a No Deal Brexit. (Photo by Peter Summers/Getty Images)(Photo by Peter Summers/Getty Images) Peter Summers Getty Images

Lib Dem leader Jo Swinson said: “We simply cannot afford to wait until 19 October to see whether or not the Prime Minister will refuse to obey the law again.

“Liberal Democrats will be working with and talking with people across the different parties to find a way to remove that threat of a no deal Brexit more quickly. It is vital that we do this for our country’s future.”

A change to the Brexit extension deadline could bring forward the date of the expected general election, as Labour has made clear it will table a vote of no confidence in Mr Johnson as soon as no-deal has been definitively ruled out.

The precise means for forcing an earlier date has not yet been determined, but Ms Swinson said her party would be considering “all options”.

Lib Dem sources confirmed that talks were taking place with cross-party opponents of a no-deal Brexit across the Commons, who would have to unite behind any initiative to drive it through parliament.

Jo Swinson (REUTERS)

The development came as Lib Dem deputy leader Sir Ed Davey warned that the Benn Act’s provisions to block no-deal may not be “watertight”.

Sir Ed told BBC Radio 4’s Today programme: "The key thing of course is implementing the extension of article 50 so that we can get no-deal totally off the table.

“It might need an extra law, who knows? The key thing is the implementation of the extension of article 50.”

Asked if the bill was watertight, Sir Ed said: “I’ve certainly seen the opinion of a number of very notable lawyers, that it’s not watertight – and if that’s the case we may need another bill to ensure that no-deal Brexit is completely taken off the table.