Otmar Issing and CNBC's Rick Santelli discussed the future of the European Union and the consequences of Brexit.
"For a substantial time to come, we have to live in the situation [where] the euro is to survive without a political union," Issing said. "It's going to be a very difficult time for the U.K. itself to manage the Brexit, to guarantee the free movement of trade."
Issing is a former ECB member and president of the Center for Financial Studies.
This interview is an exclusive for CNBC PRO subscribers.
