Former U.S. Treasury secretaries say Brexit would make Britain poorer and smaller

A British Union flag and an European Union flag are seen flying above offices in London, Britain, March 30, 2016.

US: Britain will be poorer, more inward looking and London's role as a global financial center could be undermined if it votes to leave the European Union in a June 23 referendum, eight former U.S. Treasury secretaries said on Wednesday.

"A vote to leave Europe represents a risky bet on the country’s economic future," the former U.S. Treasury secretaries said in an open letter to The Times newspaper.