If the UK and EU fails to reach an agreement on Britain leaving the single bloc a nightmare scenario could rip through the continent, business chiefs fear.
German exports could fall by 57 per cent with tariffs and customs barriers hitting trade, according to Cologne’s IW economic institute.
Sectors that would be hardest hit include logistics, car making, aerospace, pharmaceuticals and chemicals, Germany’s powerful BDI industrial lobby warned in a report published this week.
BDI managing director Joachim Lang said: “The next EU summit in two weeks must bring a breakthrough in the talks.
“Otherwise, Europe is in danger of sliding into a disorderly Brexit.
“The result would be a massive crisis.”
In the IW report, researcher Markus Jung warned of the dangers ahead.
Mr Jung said: “This horror scenario should push policy makers into constructive action.”
It comes amid mounting fears of a no-deal Brexit ahead of a crunch EU leaders’ summit on October 17.
German companies have already been hit by Brexit fears.
Chemicals and pharmaceutical firms have each spent up to £88m (100m euros)to prepare, according to Mr Lang.
He said: “That’s money they certainly could have used for other purposes.”
A transition period until 2020 was vital for German businesses, he added.
New customs arrangements would be “a negative deviation from the status quo”.
Any new customs agreement “can’t be welcomed by industry in either Great Britain or continental Europe, Mr Lang said.