Germany's BGA foreign trade group has warned of the "dire consequences" of a Brexit for all sides. It added that it would be a severe blow to the German economy too, given the two countries' close trade relations.
The head of the Federation of German Wholesale, Foreign Trade and Services (BGA), Anton Börner, warned in Berlin on Monday that a possible UK exit from the European Union would be lose-lose for everyone involved.
For Brits, a Brexit would immediately impact their nation's financial market, he argued, expecting even higher pressure on the already weak pound against the dollar and the euro.
Börner said there was no blueprint for post-Brexit negotiations between the UK and the remainder of the European Union, with import tariffs and restricted EU market access being a realistic possibility in his opinion.
The BGA chief said a Brexit would be a severe blow for the German economy too. Britain is the country's third-most important export market. German shipments there currently amount to 89 billion euros ($100 billion) annually.
German carmakers as well as producers of auto parts and pharmaceutical items would be particularly affected, he said.
Börner mentioned that some 2,500 German firms were active in Britain, with some 3,000 British firms operating in Germany. He expected mutual investments to drop after a Brexit.
But the BGA said there was a good possibility that a Brexit could have a snowball effect in the mid-term, leading other countries in the EU with strong euroskeptic populations to also hold referendums on their membership in the bloc.
Börner said people should not be tricked into believing that nation states on their own would be able to get better trade deals with others than they would when using the EU bloc's overall economic clout at the negotiating table.