At the end of January 2016 Bank of England governor Mark Carney stated during an appearance before MPs of the Treasury Select Committee that a British vote to leave the European Union would add a “risk premium” to Britain in an “increasingly febrile” global economy. He justified his answer based on Britain's current account deficit. He explained his position as follows:
Based on these comments as well as other factors, leading investment bankers Goldman Sachs warned shortly thereafter, in February 2016, that the pound could lose one-fifth of its value in if UK voted to leave the European Union. According to them the British pound could fall sharply crashing to as low as $1.15 US or $1.20 US. George Cole, a Goldman Sachs economist, stated that leaving the EU would “increase uncertainty, weigh on the UK outlook and raise concerns of foreign investors”, resulting in “an abrupt and total interruption to incoming capital flows”. Bank of England Governor Carney confirmed these fears at the beginning of March 2016, when he again appeared before the Commons Treasury Select Committee and stated that Brexit is the "biggest domestic risk to financial stability".
By Steven Swinford, Deputy Political Editor, The Telegraph, 26 Jan 2016, video source ITN