The head of the car group that owns Vauxhall has compared a no-deal Brexit to a head-on train crash.
PSA chief Carlos Tavares also said if a no-deal Brexit had serious consequences for the car group, there would be an ethical responsibility to protect employees outside the UK.
He said the firm would take “necessary decisions” regarding PSA’s UK plants.
PSA also said it had halted investment at its UK factories while the outcome of Brexit remains unclear.
Mr Tavares, who was speaking at the Frankfurt Motor Show on Tuesday, has warned previously that Vauxhall plants at Ellesmere Port and Luton were under threat from Brexit.
‘Jobs at stake’
Mr Tavares castigated politicians on both sides for failing to find a solution to Brexit. Sending two trains to crash into one another at speed in order to demonstrate their muscles and determination, he said, did not seem to be the best approach.
In June, PSA Group announced plans to build a new version of the Vauxhall Astra at its Ellesmere Port factory in Cheshire.
However, the company made it clear the investment would only take place if a suitable Brexit deal was reached.
Also at the Frankfurt show, another PSA executive, the head of the company’s Opel and Vauxhall brands, Michael Lohscheller, said Vauxhall could not make investment decisions “without knowing what will happen” with Brexit.
Mr Lohscheller added: “Brexit could disrupt supply chains in Europe as well as Britain. There are jobs and investments at stake. Everybody needs to be aware of the responsibility.”
Meanwhile, the chief financial officer of BMW, Nicolas Peter, told the BBC that leaving the EU without a deal could force the company to cut production at its Mini plant in Oxford.
And Jaguar Land Rover’s chief executive, Ralf Speth, warned that if the supply of parts into the UK was disrupted after Brexit, that could prevent production at its UK factories.
But he added that he could not comment on the overall effects of no-deal Brexit, because he simply did not have the information he needed.
Last week, UN trade body Unctad warned that a no-deal Brexit would cost UK businesses at least $16bn (£13bn) in lost sales due to the imposition of tariffs on exports.
By its calculations, UK car exporters would be the hardest hit, losing about $5bn in sales to the EU.
However, at the time the UK’s Department for International Trade said it had signed continuity agreements with non-EU members, and that exporters would have access to the world’s “fastest growing markets through new free trade agreements”.