Shadow foreign secretary Emily Thornberry has sparked fury among Liberal Democrats by comparing Jo Swinson’s party to the Taliban over its new policy to cancel Brexit if it wins power.

Ms Thornberry is a committed Remainer who said she is “never going to be able to do anything other than campaign to remain” in any fresh referendum on Brexit.

But she said it was not “democratic” to try to overturn the result of the 2016 EU referendum without consulting voters again.

Liberal Democrats have enjoyed a surge in the polls – pulling ahead of Labour in some surveys – since Ms Swinson announced that the party will go into a general election on a policy of revoking the Article 50 letter informing the EU of Britain’s intention to quit.

Speaking to The House magazine, Ms Thornberry said: “The Lib Dems have gotten kind of Taliban, haven’t they?

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

“They’ve said they’re just going to revoke, there’s not going to be another referendum. I don’t think it’s very democratic to seek to overturn a referendum without asking the people first. I really think the only democratic way to get through this and to break the logjam is to go back to the people and trust their good sense.”

Ms Swinson responded: “Comparing a UK political party to the Taliban is ludicrous. Emily is the shadow foreign secretary, and should use language that reflects the importance of that role.”

And Lib Dem foreign affairs spokesperson Chuka Umunna said Ms Thornberry should “withdraw her inappropriate remarks”.

Mr Umunna said: “Language counts – comparing the Lib Dems to a murderous organisation is no laughing matter. It is also grossly insulting to over 23,000 of her constituents who signed the parliamentary petition for Article 50 to be revoked.”

But former leader Tim Farron adopted a more humorous approach – while also taking the opportunity to have a swipe at Jeremy Corbyn’s past meetings with representatives of Hezbollah and Hamas – tweeting: “Come on Emily, if we really were like a Middle East terrorist group, don’t you think Jeremy would’ve invited us to a conference fringe meeting before now?”

Ms Thornberry clashed with Mr Corbyn after Labour’s poor showing in the European elections, when she suggested the party should be committed to campaigning for Remain in any referendum. In an apparent act of revenge, she was passed over for the stand-in slot when the leader was absent for prime minister’s questions.

But she played down the snub, telling The House: “I’m pretty confident I’m doing it in the future. It was a decision for Jeremy and Loto [leader of the opposition’s office] to decide, it wasn’t for me.”

Thornberry and Corbyn meet with the PM of Iceland, Katrin Jakobsdottir, in Westminster in May (Getty)

And she played down the significance of Labour deputy leader Tom Watson’s call for a second referendum before a general election, saying: “It’s just how he is, isn’t it? I haven’t seen him for a while ... But he’s deputy leader and he can say what he wants.”

Ms Thornberry recently got into difficulties on TV trying to explain Labour’s position on Brexit.

But she defended the position, saying: “We are now wedded to having a second referendum because so much has changed since three years ago. The question then is what will the choice be. We don’t want to put these lousy Tory choices of no deal or Theresa May’s deal to the public. We want there to be two good choices.

“I would say ‘anything other than leaving the European Union’ is not a good choice but it would be second best. We need to have a choice that will look after jobs and the economy as best we can, which means being in the customs union and being close to the single market.