The French car manufacturer that owns Vauxhall, PSA, could retrieve all production from Ellesmere Port in Cheshire if Brexit makes the UK factory unprofitable.
The company's CEO, Carlos Tavares, told the Financial Times that the business would switch to a facility in Southern Europe to build future Vauxhall Astra and Opel Astra cars if the UK did not achieve a satisfactory result when leaving the EU.
Ellesmere port facility employs more than 1
Tavares told FT: "I prefer to put it [the Astra car] in Ellesmere harbor, but if the conditions are bad and I cannot make it profitable, then I have to protect the rest of the company and I will not do it. "
He added:" We need customs visibility for parts coming from continental Europe or from the rest of the world, and we need visibility on customs for cars coming out of the UK to continental Europe. These are the only things we need – everything else we need to take care of. "
It comes after Britain's car dealership warned Boris Johnson on Friday that a non-trade Brexit constituted an" existential threat "to the car manufacturing industry in the UK.
The Society of Motor Manufacturers and Traders said, "No-deal Brexit is simply not an option."
The PSA Group warned in June that they would only build their new Vauxhall Astra at Ellesmere. Port facility if the UK avoided a Brexit without agreement.
Astra is the best-selling model produced under the Vauxhall and Opel brands.
Several ministerial ministers have said that Boris Johnson is "turbulent" preparations to leave the EU without agreement on 31 October.
Leaving the EU without an agreement would trigger customs controls and tariffs for importers and exporters.
Michael Gove wrote in the Sunday Times and said the government is now "working on the premise" of a Brex without agreement on October 31.
Other car manufacturers in the UK have expressed concern about Brexit uncertainty.
Earlier this year Japanese car manufacturer Nissan decided to build the next X-Trail model in Japan instead of Sunderland.