May said on Sunday that Britain would be in uncharted territory if her Brexit deal is rejected by parliament
Britain began rehearsals on Monday for the upheaval of a no-deal Brexit by lining up 87 trucks at a little-used airport for a trip towards the United Kingdom's most important trading gateway to continental Europe.
With the British parliament deadlocked, the ultimate destination of the Brexit project remains unclear, with possible outcomes ranging from a disorderly departure with no deal to another referendum on European Union membership.
Prime Minister Theresa May is trying to force her Brexit deal through parliament but if it is rejected then business chiefs and investors fear the world's fifth-largest economy will leave without a deal at 2300 GMT on March 29.
"It's still hard to see any upside to Brexit," said Mike Hawes, chief executive of the Society of Motor Manufacturers and Traders (SMMT), which said new car sales in 2018 fell at their fastest rate since the global financial crisis a decade ago.
"Everyone recognises that Brexit is an existential threat to the UK automotive industry and we hope a practical solution will prevail," he said, calling for lawmakers to back May's deal to guarantee a transition period.
May said on Sunday that Britain would be in uncharted territory if her Brexit deal is rejected by parliament. A vote is due around January 15.
Facing defeat in parliament last month, May postponed a vote on her deal and pledged to seek further political and legal assurances from the EU. The EU has signalled it may try to allay the fears of May's critics but will not renegotiate the deal.
Trucks and ports
May's government has repeatedly warned that a no deal will lead to severe economic disruption, and on Monday the transport ministry was planning to test the road network to Dover, Europe's busiest ferry port.
At Manston airport in Kent, which could be used as an area for parking if there is gridlock at the port of Dover, 87 trucks were lined up, the Department for Transport said. They will drive down the motorway to Dover to see if they clog up the road network.
Pro-Europeans fear Britain's exit from the EU will undermine the West as it grapples with Donald Trump's unpredictable US presidency and growing assertiveness from Russia and China.
In an attempt to prevent the United Kingdom falling out of the EU without a deal, more than 200 lawmakers have signed a letter to May urging her to rule out a no deal.
Brexit supporters say that, while there may be some short-term disruption, in the long-term the UK will thrive outside what they cast as a doomed and excessively bureaucratic project dominated by Germany.
Boris Johnson, who helped lead the Brexit campaign, said that voters would not be scared into backing a poor deal.
"There has been for far too long a confected hysteria about no deal, and a determination to make it taboo," Johnson said.
"The public seem to think that in so far as there may be short-term challenges, they are worth meeting now, in order to gain the benefits of Brexit, in free trade and self-government."