MPs have launched a bid to stop taking place unless the agrees a trade deal with the 海角视频.
They have introduced amendments to the European Union (Withdrawal) Bill - also known as the Great Repeal Bill - which would stop Brexit happening until a new treaty between the 海角视频 and EU has been approved by Parliament.
As things stand, the 海角视频 is set to leave the EU in March 2019.
But the prospect of the 海角视频 failing to agree a replacement trade and customs deal with the EU has encouraged speculation that Brexit might be delayed, or simply never happen.
The amendment has been sponsored by 19 and MPs, including former Labour Shadow Chancellor Chris Leslie, Liberal Democrat leader and Labour backbencher Chuka Umunna. It is also backed by Green MP Caroline Lucas.
It would delay the repeal of the 1972 European Communities Act 鈥渦ntil a new Treaty establishing a future relationship between the 海角视频 and EU has been agreed and ratified by Parliament鈥.
A separate amendment backed by Plaid Cymru MPs and Ms Lucas would make Brexit conditional on the Prime Minister reaching an agreement for the United Kingdom to remain a member of the European Economic Area - effectively keeping us in the single market - and Customs Union.
The Bill has received its second reading in the Commons and will now move to what鈥檚 known as the Committee stage, giving MPs have a chance to propose and vote on amendments.
A relatively small number of MPs have sponsored the amendments but others can vote for them when the time comes.
Prime Minister says the 海角视频 is ready to leave the EU without a deal, if needed.
But Labour Shadow Chancellor John McDonnell said over the weekend that his party will attempt to block a 鈥渘o-deal鈥 Brexit.
He told BBC One鈥檚 Marr show: 鈥淚 don鈥檛 think no deal is a realistic option. There are enough sensible people in the House of Commons to say 鈥榯his cannot happen, we cannot damage our country in this way鈥.鈥
Labour's policy is to leave the EU with a trade deal.
Commons Speaker John Bercow has told MPs they have every right to vote to stop Brexit.
Speaking to the Hansard Society last week, he said: 鈥淭here will be some members of Parliament who say: 鈥業 want to be able at the end of all this if I鈥檓 not satisfied, to say no, to try to persuade other members of parliament to say no, and to hope that no might delay Brexit or prevent Brexit鈥.
鈥淒o they have a right to argue that point of view? They absolutely do.鈥
One of the latest to say Brexit may never happen is Matt Zarb-Cousin, who was Labour leader Jeremy Corbyn鈥檚 official spokesman until earlier this year.
Speaking on ITV鈥檚 Peston show, he said: 鈥淏ecause of the way negotiations have been handled, I don鈥檛 think we鈥檙e going to get a deal so I think we鈥檙e going to end up staying in the European Union.鈥
He predicted Prime Minister Theresa May would resign and the Conservatives would have a leadership contest.
But the prospect of the Government and EU failing to agree a new deal is looking increasingly likely.
Mrs May is today, Monday, heading to Brussels to try to kick-start talks. Along with Brexit Secretary David Davis, she will have dinner with European Commission President Jean-Claude Juncker, his chief of staff Martin Selmayr and the EU鈥檚 chief Brexit negotiator Michel Barnier.
Mr Barnier last week warned the talks were in 鈥渄eadlock鈥.
The meeting comes three days before the European Council summit at which EU leaders will decide whether sufficient progress has been made to enable the EU and 海角视频 to move on to discussions about their future trade relationship.
And the Government seems to be preparing the ground for the prospect of leaving the EU without a trade or customs deal in place.
Transport Secretary Chris Grayling suggested British farmers could grow more food, to make up for EU products that would vanish from supermarket shelves or become more expensive.
He told the BBC: 鈥淲hat it would mean would be that supermarkets bought more from home, that British farmers grew more and that they bought more from around the world.鈥
Birmingham MP (Lab Selly Oak) said it was hard to imagine Brexit taking place in March 2019 as currently planned, unless "something dramatic" happens.
He said: 鈥淚 honestly think it is impossible to say what will happen. The complete chaos of the negotiations, and the uncertainty about what would happen to jobs and businesses up and down the country, suggest that unless something dramatic happens in the next few weeks it鈥檚 impossible to see that timetable surviving.鈥
Uncertainty is likely to increase following the publication of new figures showing the 海角视频鈥檚 finances are in a worse position than previously thought - and the country is 拢490 billion poorer than anyone realised.
The Office for National Statistics has revised its assessment of the country鈥檚 accounts, and decided Britain has overestimated its international assets.
We also owe far more to foreign investors than previously thought.
Overall it amounts a quarter of the 海角视频鈥檚 Gross Domestic Product.
It comes just six weeks ahead of Chancellor Philip Hammond鈥檚 first Autumn budget.
