Stuttgart – German firms will lose some 9 billion euros (11.1 billion dollars) annually after Britain leaves the European Union if trade continues according to World Trade Organization (WTO) rules, a study published on Monday has found.

WTO rules would mean tariffs and regulatory barriers including licensing procedures and potentially lengthy waits at borders, which also result in costs for businesses, the report by management consultants Oliver Wyman and multinational law firm Clifford Chance says.

Car industry hit hardest

Germany would be the hardest hit of the EU member states, the report found, especially its car industry which would shoulder a third of the estimated 9-billion-euro losses.

Businesses across the bloc without Britain will face costs of 37 billion euros per year, while Britain will take a 32-billion-euro hit, the report found.

Britain and the EU are currently trying to hammer out a post-Brexit trade deal, but London's insistence that it leave the customs union with the EU and its internal market and still have unfettered access to the market is complicating negotiations; Brussels does not see how this can be realized in practice.

Uncertain times

All German firms should prepare for uncertain times, Oliver Wyman Germany's head Finja Carolin Kuetz said on Monday. Small firms could be especially hit by the new complexity of relations, she said.

"Over 60 per cent of exporting small and micro enterprises in Germany only trade within the EU and have no processes for trading outside Europe," she said.