BERLIN (Reuters) - If Britain quits the European Union after a June 23 referendum on its membership of the bloc, it could shave 3 percent off Germany’s long-term economic growth in the worst case scenario, the head of Germany’s Ifo institute said on Thursday.

“The biggest risk at the moment is a Brexit,” said Clemens Fuest, head of the Munich-based Ifo economic institute.

He added that if Britain leaves the EU, international trade would involve higher costs while there was also a risk of competitiveness declining and lower transnational investment.

“Germany has very little to gain and an awful lot to lose,” Fuest said.